Question 1 :
Under which of the following conditions is the law $pV=RT$ obeyed most closely by a real gas?
Question 2 :
Which term describes the mass of $6.022\times { 10 }^{ 23 }$ representative particles?
Question 4 :
Which of the following statements is correct regarding one mole of helium gas and one mole of neon gas ,both are at <i>STP</i><span>. </span>
Question 5 :
What happens to the density of the gas if the volume of an ideal gas is reduced to half its original volume:
Question 6 :
<span>An ideal gas is enclosed in a perfectly closed box.On increasing the temperature of the gas, which property of the gas does not change?</span>
Question 7 : <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small"><p class="wysiwyg-text-align-left">The absolute temperature T of a gas is plotted against its pressure P for two different constant <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">volumes V$_{1}$</span></span><span class="wysiwyg-font-size-xx-small"><span class="wysiwyg-font-size-xx-small"> </span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">and V$_{2}$ </span></span><span class="wysiwyg-font-size-xx-small"><span class="wysiwyg-font-size-xx-small"> </span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">where V$_{1}$</span></span><span class="wysiwyg-font-size-xx-small"><span class="wysiwyg-font-size-xx-small"> </span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">> V$_{2}$</span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">. T is plotted </span></span>along x-axis and P along y-axis.</p></span></span>
Question 9 : <p class="wysiwyg-text-align-left"><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">If </span></span><em>$\rho $</em><i> </i><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">is the density, m is the mass of 1 molecule and </span></span><span>K is the Boltzman constant for a gas then the pressure </span><span>of the gas is:</span></p>
Question 10 :
By the ideal gas law, the pressure of $0.60$ moles ${NH}_{3}$ gas in a $3.00\ L$ vessel at ${25}^{o}C$ is, given that $R=0.082\ L$ atm ${mol}^{-1}{k}^{-1}$:
Question 11 :
If pressure of a gas contained in a closed vessel is increased by $0.4\%$ when heated by $1^o$C, initial temperature must be.
Question 13 : <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small"></span></span><p class="wysiwyg-text-align-left">A certain mass of hydrogen gas is introduced into a vessel at room temperature, the final pressure of the gas in the vessel is </p>
Question 14 :
In a thermally isolated system, two boxes filled with an ideal gas are connected by a valve. When the valve is in closed position, states of the box 1 and $2$, respectively, are ($1$ atm, V.T) and $0.5$ atm, $4V$. T). When the valve is opened, the final pressure of the system is approximately
Question 15 :
Air is filled in a bottle at atmospheric pressure and it is corked at $35^o$C. If the cork can come out at $3$ atmospheric pressure, the upto what temperature should the bottle be heated in order to remove the cork.
Question 16 :
A vessel of volume V $=$ 30 l contains ideal gas at the temperature $0^\circ$ After a portion of the gas has been let out, the pressure in the vessel decreased by $\Delta p=0.78$ atm (the temperature remaining constant). Find the mass of the released gas. The gas density under the normal conditions $\rho=1.3\:g/l$
Question 17 :
One mole of an ideal gas expands against a constant external pressure of 1 atm from a volume of $10d{ m }^{ 3 }$ to a volume of $30d{ m }^{ 3 }$. What would be the work done in joules?
Question 18 :
A perfectly conducting vessel of volume V = $0.4m^{3}$ contains an ideal gas constant temperature T = 273 K. A portion of the gas is let our and the pressure of the gas falls by $\Delta P\, =\, 0.24 atm$ (Density of the gas at STP is $\rho\, =\, 1.2 kg/m^{3}$). Find the mass of the gas which excapes from the vessels.
Question 19 :
A gas thermometer measure the temperature from, the variation of pressure of a sample of gas. If the pressure measured at the melting point of lead is 2.20 times the pressure measured at the triple point of water find the melting point of lead.
Question 20 :
A glass bulb of volume $400\, cm^3$ is connected to another of volume $200\, cm^3$ by means of a tube of negligible volume. The bulbs contain dry air and both are at a common temperature and pressure of $20^{\circ}C$ and $1.00$ $atm$ respectively. The larger bulb is immersed in steam at $10^{\circ}C$ and the smaller in melting ice at $0^{\circ}C$. Find the final common pressure.
Question 21 : <p class="wysiwyg-text-align-left"><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">Two identical containers each of volume V$_{0}$</span></span><span class="wysiwyg-font-size-xx-small"><span class="wysiwyg-font-size-xx-small"> </span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">are </span></span>joined by a small pipe. The containers contain <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">identical gases at temperature T$_{0}$</span></span><span class="wysiwyg-font-size-xx-small"><span class="wysiwyg-font-size-xx-small"> </span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">and pressure </span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">P$_{0}$</span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">. One container is heated to temperature 2T$_{0}$ </span></span>while maintaining the other at the same temperature. The common pressure of the gas is P and n is the number of moles of gas in <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">container at temperature 2T$_{0}$</span></span><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">.</span></span></p>
Question 22 :
A vessel of volume V $=20 L$ contains a mixture of hydrogen and helium at a temperature $t=20^\circ$ and pressure p $=$ 2.0 atm. The mass of the mixture is equal to m $=$ 5.0 g. Find the ratio of the <span>mass of hydrogen to that of helium in the given mixture.</span>
Question 23 :
During an experiment, an ideal gas is found to obey a condition $\displaystyle \frac{P^{2}}{\rho}\, =\, constant\, (\rho\, =\, density\, of\, the\, gas)$ The gas is initially at temperature T, pressurre P and density $\rho$. The gas expands such that density changes to $\rho/2$
Question 24 :
An air bubble of volume V is released from the bottom of a lake which has a depth of 11 m. Find the volume of the bubble at the surface of the lake. The water has density $1000\, kg/m^{3}$. At the release point of the bubble and at the surface, temperature is $4^{\circ}\,C$. The atmospheric pressure is $1.01\, \times\, 10^{5}\, N/m^{2}$.
Question 25 :
The volume of mole of a prefect gas at NTP is <span>______.</span>
Question 27 :
The pressure inside a liquid of density $\rho$ at a depth $h$ is :
Question 28 :
Three containers are used in chemistry lab. All containers have same bottom area and the same height. A chemistry student fills each of the containers with same liquid to the maximum volume. Which of the following is true about the pressure on the bottom for each container?<br>
Question 29 :
Pressure at free surface of a water lake is ${P}_{1}$, while pressure at a depth $h$ below its free surface is ${P}_{2}$. Which of the following is/are true (Density of liquid is $\rho$)
Question 30 :
A capillary tube of radius $r$ is immersed in water and water rises in it to a height $h$. Mass of water in the capillary tube is $m$. If the radius of the tube is doubled, mass of water that will rise in the capillary tube will now be
Question 31 :
When a bubble, released from the bottom of a lake, rises near the water surface, it
Question 33 :
The height of a water column which will exert on its base the same pressure as the $70 cm$ column of mercury. Density of mercury is $13.6 g c{m}^{-3}$ is $x \ m$. Find [$x$].(where , [] is step function)<br/>
Question 34 :
Two capillaries of same length and radii in the ratio 1: 2 are.connected in series. A liquid flows through them in streamlined condition. If the pressure across the two extreme ends of the combination is 1 m of water, the pressure difference across first capillary is
Question 35 :
What is the mass of $2$ litres of nitrogen at $22.4$ atmospheric pressure and $273\ K$
Question 37 :
Assertion: A body having the uniform density has same point, as centre of gravity and centre of buoyancy
Reason: While formulating the equation for positioning centre of mass and centre of buoyancy,has difference of the term of uniform density only.
Question 38 :
The pressure of water on the ground floor is $40,000 Pa$ and on the first floor is $10,000 Pa$. The height of the first floor is $x \ m.$ Then $x=?$<br/>(Take : density of water = $1000 kg {m}^{-3}$, $g=10 m {s}^{-2}$)
Question 40 :
A capillary tube of radius $r$ is immersed in water and water rises to a height of $h$. Mass of water in the capillary tube is $5\times 10^{-3}kg$. The same capillary tube is now immersed in a liquid whose surface tension is $\sqrt{2}$ times the surface tension of water. The angle of contact between the capillary tube and this liquid is $45^o$. The mass of liquid which rises into the capillary tube now is (in kg):
Question 41 :
A capillary tube with inner cross-section in the form of a square of side a is dipped vertically in a liquid of density $ \rho $ and surface tension $ \sigma $ which wet the surface of capillary tube with angle of contact $ \theta $. The approximate height to which liquid will be raised in the tube is : (Neglect the effect of surface tension at the corners of capillary tube)
Question 42 :
Consider the equations $P = \displaystyle \lim_{\triangle S\rightarrow 0} \dfrac {F}{\triangle S}$ and $P_{1} - P_{2} = \rho gz$.<br>In an elevator accelerating upward.
Question 43 :
A liquid is flowing in a horizontal uniform capillary tube under a constant pressure difference p. The value of pressure for which the rate of flow of the liquid is doubled when the radius and length both are doubled, is
Question 44 :
A spherical tank of 1.2 m radius is half filled with oil of relative density 0.8. if the tank is given a horizontal acceleration of $10 m/s^2$, the maximum pressure on the tank is $\sqrt{2 p}$ pascal. Find the value of P.
Question 46 :
Morning sun is not so hot as the mid day sun because :
Question 47 :
For two bodies (which are in contact with each other) to be in thermal equilibrium, they must be separated by :
Question 49 :
According to the principle of heat exchange which expression is true from below:<br>
Question 50 :
A boy of mass 50 kg runs up a staircase of 45 steps in 9 s. If the height of each step of the staircase is 15 cm, find the power of the boy.
Question 51 :
Which of the following parameters does not characterize the thermodynamic state of matter?
Question 53 :
Which of the following parameters does not charaterize the thermodynamic state of matter?
Question 54 :
The following three objects (1) a metal tray, (2) a block of wood, and (3) a woolen cap are left in a closed room overnight. Next day the temperature of each is recorded as ${ T }_{ 1 }$, ${ T }_{ 2 }$ and ${ T }_{ 3 }$ respectively. The likely situation is
Question 55 :
A container is filled with 20 moles of an ideal diatomic gas at absolute temperature T. When heat is supplied to gas temperature remains constant but 8 moles dissociate into atoms. Heat energy given to gas is
Question 56 :
Soda bottles are made of thick glass so that they can withstand an increase in :
Question 57 :
Figure shows two flasks connected to each other. The volume of the flask 1 is twice that of flask 2. The system is filled with an ideal gas at temperature 100 K and 200 K respectively in the flasks. If the mass of the gas in 1 m, then what is the mass of the gas in flask 2 in equilibrium?
Question 58 :
Assertion: The zeroth law of thermodynamics was known before law I of thermodynamics.
Reason: The zeroth law concerning thermal equilibrium was appeared after three laws (I, II and III) of termodynamics and thus was named as zeroth law.
Question 59 :
For a first order reaction rate constant is $1 \times {10^{ - 5}}{\sec ^{ - 1}}$ having ${E_a} = 1800\ kJ/mol$ . Then the value of $\ell nA$ at$T = 600\ K$ is:-
Question 60 :
$300$ gm of water at $25^o$C is added to $100$gm of ice at $0^oC$ . Final temperature of the mixture is:
Question 61 :
In a thermodynamic process pressure of a fixed mass of a gas is changed in such a manner that the gas releases $20J$ of heat and $8J$ of work is done on the gas. If initial internal energy of the gas was $30J$, what will be the fixed internal energy?
Question 62 :
Zeroth law of thermodynamics is not valid for which one of the following ?
Question 63 :
An insulated container containing monoatomic gas of molar mass m is moving with a velocity $v_0$. If the container is suddenly stopped. The change in temperature is?
Question 64 :
A cylinder of mass $1$kg is given heat of $20000$J at atmospheric pressure. If initially temperature of cylinder is $20^o$C, find change in internal energy of the cylinder.<br>(Given that Specific heat capacity of cylinder $=400$J $kg^{-1}$ $^0C^{-1}$, Coefficient of volume expansion $=9\times 10^{-5}$ $^0C^{-1}$, Atmospheric pressure $=10^5$ $N/m^2$ and Density of cylinder $=9000$ $kg/m^3$).<br>
Question 65 :
Consider a rectangular block of wood moving with a velocity $v_0$ in a gas at temperature T and mass density $\rho$. Assume the velocity is along x-axis and the area of cross-section of the block perpendicular to $v_0$ is A. The drag force on the block is (where m is the mass of the gas molecule).
Question 66 :
The increase of pressure on ice $\rightleftharpoons$ water system at constant temperature will lead to:
Question 67 :
"Heat cannot by itself flow from a body at lower temperature to a body at higher temperature" is a statement of the consequence of
Question 68 :
Two thermally insulated vessels 1 and 2 are filled with air at temperature $(\mathrm{T}_{1}, \mathrm{T}_{2})$, volume $(\mathrm{V}_{1}, \mathrm{V}_{2})$ and pressure $(\mathrm{P}_{1}, \mathrm{P}_{2})$ respectively. If the valve joining the two vessels is opened, the temperature inside the vessel at equilibrium will be: <br/>
Question 71 :
Calculate the period and frequency for the second hand, minute hand, and hour hand of a clock.
Question 72 :
The period of a pendulum is 0.20 seconds. What is the frequency of the pendulum?
Question 73 :
Time period of oscillation of a spring is $12$s on earth. What shall be the time period if it is taken to moon?
Question 75 :
A particle of mass $m$ moving along the $x-$ axis as a potential energy $U(x)=a+bx^2$ where $a$ and $b$ are positive constants. It will execute simple harmonic motion with a frequency determined by the value of :
Question 76 :
A particle is moving on a circle with uniform speed. Its motion is<br>
Question 77 :
A particle executes simple harmonic motion between $x=-A$ and $x=+A$. The time taken for it to go from $0$ to $A/2$ is $T_1$ and to go from $A/2$ to A is $T_2$. Then.
Question 78 : By suspending a mass of 0.50 kg, a spring is stretched by 8.20 m. If a mass of 0.25 kg is suspended, then its period of oscillation will be :<div>(Take g = 10 $ms^{-2}$)<br/></div>
Question 79 :
A mass m is suspended from a spring of force constant $k.$ The angular frequency of oscillation of the spring will be<br>
Question 80 :
The differential equation representing the SHM of a particule is $\dfrac { { 9d }^{ 2 }y }{ { dt }^{ 2 } } $ $+ 4y = 0.$ The time period of the particle is given by :
Question 82 :
If a SHM is given by y = ($sin \omega t + cos \omega t$)m, which of the following statement is true?
Question 83 :
How long will it be moving until it stops for the first time?
Question 84 :
The amplitude and the periodic time of a SHM are $5cm$ and $6s$ respectively. At a distance of $2.5cm$ away from the mean position, the phase will be
Question 85 :
A particle is performing SHM of amplitude "A" and time period "T". Find the time taken by the particle to go from 0 to A /$\sqrt{2}$.
Question 87 :
Assertion: Path of a particle in SHM is always a straight line.
Reason: All straight line motions are not simple harmonic.
Question 88 :
A particle moves along the $x$-axis according to the equation $x = 10 sin3 ( t )$. The amplitudes and frequencies of component SHMs are<br/>
Question 89 :
The time taken by a particle performing S.H.M. to pass from point A to B where its velocities are same is $2$ seconds. After another $2$ seconds, it returns to B. Determine the time period of oscillation is (in seconds).
Question 90 :
A particle executing S.H.M. completes a distance (taking friction as negligible) in one complete one time period.
Question 91 :
The displacement of a body executing SHM is given by x = A sin (2$\pi t$ + $\dfrac{\pi} {3}$). The first time from t = 0 when the velocity is maximum is:
Question 92 :
Assertion: In $SHM$, acceleration is always directed towards the mean position.
Reason: In $SHM$, the body has to stop momentary at the extreme position and move back to mean position.
Question 93 :
A small solid cylinder of mass M attached to a horizontal massless spring can roll without slipping along a horizontal surface. find its time period.
Question 94 :
The angular frequency of a spring block system is $\omega _{0}$ This system is suspended from the ceiling of anelevator moving downwards with a constant speed v$_{0}$. The block is at rest relative to the elevator. Lift issuddenly stopped. Assuming the downwards as a positive direction, choose the wrong statement:
Question 95 :
The real force 'F' acting on a particle of mass 'm' performing circular motion acts along the radius of circle 'r' and is directed towards the centre of circle. The square root of magnitude of such force is? (T$=$ periodic time)
Question 96 :
The angular velocity of rotation of hour hand of a watch is how many times the angular velocity of Earth's rotation about its own axis?
Question 97 :
State whether the following statements are true or false by writing T'F against them.<br>In a uniform circular motion. the speed continuously changes because of the direction of motion<span> changes.</span>
Question 98 :
A particle is moving along a circle such that it completes one revolution in $40$ seconds. In $2$ minutes $20$ seconds, the ratio $\cfrac { \left| displacement \right| }{ distance } $ is
Question 100 :
Assertion: Circular and projectile both are two dimensional motion. But in circular motion we cannot apply $\displaystyle \vec{v}= \vec{u}+\vec{a}t$ directly, whereas in projectile motion we can.
Reason: Projectile motion takes place under gravity, while in circular motion gravity has no role.
Question 101 :
An object of mass $m$ moves with constant speed in a circular path of radius $R$ under the action of a force constatn magnitude $F$. The kinetic energy of object is
Question 102 :
A cyclist turns a corner with a radius of 50 m at a speed of 20 m/s . What is the magnitude of the cyclist's acceleration?
Question 103 :
A body rotates at $300$ rotation per minute. The value in radian of the angle described in $1$ sec is
Question 104 :
A particle starts travelling on a circle with constant tangential acceleration. The angle between velocity vector and acceleration vector, at the moment when particle complete half the circular track, is:
Question 105 :
A particle has initial velocity, $\displaystyle \vec{v}=3\hat{i}+4\hat{j}$ and a constant force $\displaystyle \vec{F}=4\hat{i}-3\hat{j}$ acts on it. The path of the particle can be:
Question 106 :
Velocity of a particle varies as $\vec{V}=y\hat{i}-x\hat{j}$ under the effect of a single variable force. Then<br/>
Question 107 :
A wheel has moment of inertia $10^{-2} kg-m^2$ and is making 10 rps. The torque required to stop it in 5 secs is
Question 108 :
A merry-go-round, made of a ring-like platform of radius R and mass M. is revolving with angular speed $\omega$? A person of mass M is standing on it. At one instant., the person jumps off the<br>round, radially away from the center of the round (as seen from the round). The speed of the round afterwards is:
Question 109 :
The velocity of a car travelling on a straight road is $3.5km{ h }^{ -1 }$ at an instant of time. Now travelling with uniform acceleration for $10s$ the velocity becomes exactly double. If the wheel radius of the car is $25cm$, then which of the following is the closest to the number of revolutions that the wheel makes during this $10s$?
Question 110 :
A wheel is making Revolution about axis with uniform angular acceleration, Starting from rest, it reaches $100\ rev/sec$ in $4\ seconds$. Find the angular rotated during these four seconds.
Question 111 :
Assertion: Work done by friction force in case of pure rolling,is equal to change in rotational energy.
Reason: Ratio of kinetic energy of rotation to kinetic energy of translation is fixed for every case.
Question 112 :
A disc rotates about its axis with a constant angular acceleration of $4$ rad$/s^2$. Find the radius tangential accelerations of a particle at a distance of $1$ cm from the axis at the end of the second after the disc starts rotating.
Question 113 :
A particle of mass $10\ g$ moves along a circle of radius $6.4\ cm$ with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to $8 \times {10}^{-4} J$ by the end of the second revolution after the beginning of the motion?
Question 114 :
Two particles move on a circular path (one just inside and the other just outside) with angular velocities $\omega $ and $ 5 \omega $ starting from the same point. Then:<br>
Question 116 :
The shape of wave front at a very large distance from source is ______
Question 121 :
which one of the following phenomenon is not explained by Huygen's construction of wavefront
Question 122 :
When the orange light passes from air ($n = 1$) into glass ($n = 1.5$), what is its new wavelength?
Question 123 :
In case of linearly polarised light, the magnitude of the electric field vector.
Question 126 :
A person find that the Sun rays reflected by the still water in a lake are polarized. If the refractive index of water is $1.327$, then sun will be seen at the angle of ___________ with the horizon.
Question 127 :
On reflection from a plane surface, the following two characteristics get changed :<br>
Question 128 :
When light suffers reflection at the interface between water and glass, the change of phase in the reflected wave is
Question 129 :
The wavefront of a light beam is given by the equation $x + 2 y + 3 z = c$ , (where c is arbitrary constant) then what<span> is the angle made by the direction of light with the y-axis?</span>
Question 130 :
A ray of light is incident from a denser to a rarer medium. The critical angle for total internal reflection is $\theta_{iC}$ and the Brewster's angle of incidence is $\theta_{iB}$, such that $sin\theta_{iC}/sin\theta_{iB}=n=1.28$. The relative refractive index of the two media is :
Question 131 :
What is the wavelength of light for the least energetic photon emitted in the Lyman series of the hydrogen spectrum. (take hc = 1240 eV nm)
Question 132 :
If the polarizing angle of a piece of glass for green light is 54.74$^{o}$, then the angle of minimum deviation for an equilateral prism made of same glass is :<br/>[GIVEN, tan 54.74$^{o}$ = 1.414]
Question 133 :
A wave or a pulse is reflected normally from the surface of a denser medium back into the rarer medium. The phase change caused by the reflection-
Question 134 :
Assertion: The unpolarised light and polarised light can be distinguished from each other by using polaroid.
Reason: A Polaroid is capable of producing plane polarised beams of light.
Question 136 :
Two stretched strings have lengths l and 2l while tension are T and 4T respectively. If they are made of same material the ratio of their frequency is:
Question 138 :
What happens when a sound wave is reflected from the boundary of a denser medium? The compression of the incident wave is returned as a
Question 139 :
M<span>ark the correct statements.<br/>(I) </span>directions in which the sound is incident and is reflected make equal angles with the normal to the reflecting surface.<br/>(II) reflection of sound occurs from a polished surface.<br/>(III) reflection of sound occurs from rough surface.
Question 140 :
Fill the vacant space with the suitable option. A wave transfers ______from one location to another.<br/>
Question 141 :
An ultrasonic source emits sound of frequency 220 kHz in air. If this sound meets a water surface, what is the wavelength of the transmitted sound? (At the atmospheric temperature, speed of sound in air $=352 m s^{-1} and in water = 1.496 m s^{-1}$)<br>
Question 142 :
The relation between frequency $\upsilon$, wavelength $\lambda$ and velocity of propagation of wave $\nu$ is
Question 143 :
Assertion - On reflection from a rigid boundary there takes place a complete reversal of phase.<br/>Reason - On reflection from a denser medium, both the particle velocity and wave velocity are reversed in sign.
Question 144 :
A plane progressive wave of frequency $25 Hz$, amplitude $2.5 \times 10^{-5}m$ and initial phase zero moves along the negative x-direction with a velocity of $300 ms^{-1}$ . A and B are two points $6m$ apart on the line of propagation of the wave. At any instant the phase difference between A and B is $\Theta$ . The maximum difference the displacement of the particles at A and B is $\Delta$ , then<br/>
Question 145 :
If two waves of length $50 cm$ and $51 cm$ produced $12$ beats $per\ second$, the velocity of sound is:
Question 146 :
What is produced at a rigid reflecting plane for a displacement wave?
Question 148 :
The frequency of a fork is 500 Hz. The velocity of sound in air is 350 ms$^{-1}$. The distance through which sound travels by the time the fork makes 125 vibrations is <br>
Question 150 :
A point source emits sound equally in all directions in a non-absorbing medium. Two points $P$ and $Q$ are at distance of $2\ m$ and $3\ m$ respectively from the source. The ratio of the intensities of the wave at $P$ and $Q$ is:
Question 151 :
Assertion: The decrease in speed of sound at high altitudes is due of fall in pressure at this altitude.
Reason: The speed of sound is the same at all pressures and varies with temperature only.
Question 152 :
The displacement $y$ of a particle, if given by $y=4\cos^2\left(\dfrac{t}{2}\right)\sin(1000t)$. This expression may be considered to be a result of the superposition of how many simple harmonic motions?
Question 153 :
A wave is represented by the equation $y=A\sin(10\pi x+15\pi t+\pi /3)$, where $x$ is in metres and $t$ is in seconds. What is the wavelength of this wave travelling in the positive x-direction?<br/>
Question 154 :
Write the equations for the displacement as a function of time at $3\space m$ of the boy's end of the clothesline
Question 155 :
Which of the following does not represent a standing wave :<br/>
Question 156 :
A wave travelling along positive x-axis is given by $=A\sin { \left( \omega t-kx \right) } $. If it is reflected from a rigid boundary such that $80$% amplitude is reflected, then equation of reflected wave is
Question 157 :
Assertion: Sound shadows are generally not so well defined as those of light.
Reason: The wavelength of sound waves are very large in comparison to that of light waves.
Question 158 : <div>A person standing between the two vertical cliff produces a sound. Two successive echoes are heard at 4 s and 6 s. Calculate the distance between the cliffs : <br/></div><div>(Speed of sound in air $= 320 m s^{-1}$)</div>
Question 160 :
Two wires having different densities are joined at $\displaystyle x=0.$ An incident wave $\displaystyle y = A_0 sin (\omega t - k_1 x)$ travelling to the right in the wire $\displaystyle x \leq 0.$ If $\displaystyle K_2$ is the wave vector of the transmitted wave, then the ratio of the amplitude of the reflected wave to that of the incident wave is:
Question 162 : State whether True or False :<div>If electric current is passed through metal body then it behaves as magnet.<br/></div>
Question 163 :
A charged particle moving in a magnetic field experiences a resultant force ?
Question 164 :
A proton moving with a velocity V is acted upon by electric field E and magnetic field B. The proton will move undeflected if<br>
Question 165 :
In cyclotron, radius of circular path traced by positive ions is ____________.
Question 166 :
Which of the following effects of current does not depend on the direction of current?
Question 167 :
Assertion: A stationary charged particle in a magnetic field does not experience a force.
Reason: The force acting on a charged particle does not depend on velocity of the particle.
Question 168 :
A proton, an alpha particle and an electron are projected perpendicularly into uniform transverse electric and magnetic fields. It is observed that proton travels undeflected. Then,<br/>a) deflection for alpha particle > deflection for proton<br/>b) alpha particle travels in clockwise, and electron in anti-clockwise directions.<br/>c) both alpha particle and electron travel without deflection<br/>d) alpha particle gets deflected but not electron.<br/>
Question 170 :
A proton is moving along Z-axis in a magnetic filed.The magnetic filed is along X-axis.The proton will experience a force along <br>
Question 171 :
A charged particle moves in a gravity free space where an electric field of strength E and a magnetic field of induction B exist. Which of the following statement is/are correct?<br>
Question 172 :
Two long thin parallel conductor are kept very close to each other without touching. One carries a current $i$ and the other has charge $\lambda$ per unit length. An electron moving parallel to the conductor is undeflected. lf $c$ is the velocity of light. then :<br/>
Question 173 :
A horizontal wire 0.1 m long carries a current of 5 A. Find the magnitude of the magnetic field, which can support the weight of the wire. Assume wire to be of mass $3 \times 10^{-3}kg m^{-1}$ :<br/>
Question 174 :
Assertion: A charged particle moves along positive y-axis with constant velocity in uniform electric and magnetic fields.If magnetic field is acting along positive x-axis,then electric field should act along positive z-axis.
Reason: To keep the charged particle undeviated the relation $\vec{E}=\vec{B}\times \vec{v}$ must hold good.
Question 175 :
<br>Two protons move parallel to each other, keeping distance $\mathrm{r}$ between them, both moving with same velocity $\vec{\mathrm{v}}$. Then the ratio of the electric and magnetic force of interaction between them is:<br>(c - Velocity of light)
Question 176 :
Kirchhoff's law of junction, $\displaystyle \sum { I } =0$, is based on
Question 177 :
Best method to increase the sensitivity of the moving coil galvanometer is to decrease<br/>
Question 179 :
A lamp of 6 V and 30 W is used in a laboratory but the supply is of 120 V. what will be done to make use of the lamp?<br>(1) A resistance may be used<br>(2) A resistance may be used in series with lamp.<br>(3) The resistance should be of 18 $\Omega$.
Question 180 :
<strong>Which of the following is likely to have the largest resistance?</strong><br>
Question 181 :
Write true or false for the following statements :<br>Battery is a source of maintaining a constant potential difference across two ends of a conductor.
Question 183 :
An ammeter is always connected in series in a circuit because<br>
Question 184 :
<span>Kirchhoff's voltage law states that the algebraic sum of the product of resistance and current in each part of any closed circuit is equal to the algebraic sum of the emf's in that closed circuit.</span>State which law is this.
Question 185 :
A galvanometer of 50 gives full scale deflection with 2 mA current as to convert it into ammeter range of 10 A is connected with it then shunt resistance will be<br/>
Question 186 :
An unknown resistance $R_1$ is connected in series with a resistance of 10 ohm. This combination is connected to one gap of a metre bridge, while other gap is connected to another resistance $R_2$. The balance point is at 50 cm. Now, when the 10 ohm resistance is removed, the balance point shifts to 40 cm.Then, the value of $R_1$ is
Question 187 :
A coil of resistance $40\Omega$ is connected to a galvanometer of $160\Omega$ resistance. The coil has radius $6$mm and turns $100$. This coil is placed between the poles of a magnet such that magnetic field is perpendicular to coil. If coil is dragged out then the charge through the galvanometer is $32\mu C$. The magnetic field is?
Question 188 :
In a Wheatstone's bridge, three resistances P,Q and R are connected in three arms and the fourth arm is formed by two resistances $S_{1}$ and $S_{2}$ connected in parallel. The condition for the bridge to be balanced will be :<br/>
Question 189 :
Assertion: A soft iron core is used in a moving coil galvanometer to increase the strength of magnetic field.
Reason: From soft iron more number of the magnetic lines of force passes.
Question 190 :
Two unknown resistances are connected in two gaps of a meter-bridge. The null point is obtained at $40\ cm$ from left end. A $30\Omega$ resistance is connected in series with the smaller of the two resistances, the null point shifts by $20\ cm$ to the right end. The value of smaller resistance in $\Omega$ is
Question 191 :
The intensity of magnetic fields at a distance $d$ from an isolated pole of $m$ units in the air is
Question 192 :
The ratio of magnetic induction of magnetic field strength in a medium gives magnetic permeability.<br>
Question 193 :
The value of relative magnetic permeability $(\mu_r$) for ferromagnetic materials is
Question 194 :
A bar magnet has a magnetic moment of $200$ $A{m}^{2}$. The magnet is suspended in a magnetic field of $0.30\ N{A}^{-1}{m}^{-1}$. The torque required to rotate the magnet from its equilibrium position through an angle of ${30}^{o}$ will be:
Question 195 :
A long solenoid has 1000 turns per meter and carries a current of 1 A. It has a soft Iron core of $ u_{r}= 1000 $. The core is heated beyond the Curie temperature, $ T_{e^{-}} $
Question 196 :
The relation between magnetic susceptibility ${ \chi }_{ m }$ and relative permeability ${ \mu }_{ r }$ is
Question 197 :
A bar magnet of magnetic moment $200A-m^{2}$ is suspended in a magnetic field of intensity 0.25 NA - m . The couple required to deflect it through 30$^{0}$ is
Question 198 :
The relative permeability is represented by $\mu_{r}$ and the susceptibility by $\chi$ for a magnetic substance. Then for a paramagnetic substance.
Question 199 : <span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"></span></span><p class="wysiwyg-text-align-left">A bar magnet of length $10\ cm$ and pole strength $2\ Am$ makes an angle $60^{o}$ with a uniform magnetic field of induction $50T$. The couple acting on it :<br/></p>
Question 200 :
A magnetic needle is placed parallel to a magnetic field. The amount of work done in rotating the coil by an angle of 60$^0$ is W units. Then, the torque required to keep the needle in the displaced position is
Question 201 :
An electron having mass $9.1\times 10^{-31}$ kg, charge $1.6\times 10^{-19}$C and moving with the velocity of $10^6$ m/s enters a region where magnetic field exists. If it describes a circle of radius $0.2$m then the intensity of magnetic field must be ___________$\times 10^{-5}$T.
Question 202 :
If relative permeability of iron is 2000. Its absolute permeability in S.I. units is
Question 203 :
A rod of ferromagnetic material with dimension $10 \times 0.5 \times 0.2 cm^3$ is placed in a magnetic field of strength $0.5 \times 10^4 Am^{-1}$ as a result of which a magnetic field of $5 Am^{-2}$ is produced in the rod. The value of magnetic induction will be
Question 204 :
A magnet of magnetic moment $10 \hat{i} A-m^2 $ is placed along the x-axis in a magnetic field $ \overline{B} = ( 2 \hat {i} + 3 \hat{j} ) T $ . The torque acting on bar magnet is :
Question 205 :
An electron of charge e and mass m is moving in circular path of radius r with a uniform angular speed . Then which of the following statements are correct?
Question 206 :
A coil of insulated wire is connected to a battery. If it is taken to galvanometer, its pointer is deflected, because<br/>
Question 208 :
A coil of insulated copper wire is connected to a galvanometer. What would happen if a bar magnet is (i) Pushed into the coil?
Question 212 :
Assertion: Induced potential across a coil and therefore induced current is always opposite to the direction of current due to external source.
Reason: Lenz's law state that induced emf always opposes the cause due to which it is being produced.
Question 213 :
State whether given statement is True or False<br/>A device which receives and then transmits electromagnetic signal in an artificial satellite is called transponder.<br/><br/>
Question 215 : Read the following statements and answer whether the given statement is true or false.<div><br/></div><div>The Lenz's law is consistent with the law of conservation of energy.<br/></div>
Question 216 :
A wire in the form of a circular loop of radius $10cm$ lies in a plane normal to a magnetic field of $100T$. If this wire is pulled to take a square shape in the same plane in $0.1s$, find the average induced emf in the loop.
Question 217 :
A hundred turns of insulated copper wire are wrapped around an iron cylinder of area $1 \times 10^{-3}m^2$ and are connected to a resistor. The total resistance in the circuit is 10 ohms. If the longitudinal magnetic induction in the iron changes from 1 weber $m^{-2}$, in the direction to 1 Weber $m^{-2}$ in the opposite direction, how much charge flows through the circuit
Question 218 :
A plane electromagnetic wave in a non magnetic dielectric medium is given by $\bar{E} = \bar{E_0} ( 4 \times 10^{-7}x - 50 t)$ with distance being in meter and time in seconds. The dielectric constant of the medium is:
Question 219 :
A rod of $10cm$ length is moving perpendicular to uniform magnetic field of intensity $5\times { 10 }^{ -4 }Wb/{ m }^{ 2 }$. If the acceleration of the rod is $5m/{s}^{2}$, then the rate of increase of induced emf is _______
Question 224 :
Let S be the set of all points in a plane. Let R be a relation on S such that for any two points a and b, aRb iff b is within 1 cm from a. Then R is
Question 225 :
In a region of space having a uniform electric field $E$, a hemispherical bowl of radius $r$ is placed. The electric flux $\phi$ through the bowl is
Question 226 :
A solid sphere of radius ${ R }_{ 1 }$ and volume charge density $p=\frac { { p }_{ 0 } }{ r } $ is enclosed by a hollow sphere of radius ${ R }_{ 2 }$ with negative surface charge density $\sigma $, such that the total charge in the system is zero. ${ p }_{ 0 }$ is a positive constant and r is the distance from the centre of the spheere. The ratio ${ R }_{ 2 }/{ R }_{ 1 }$ is
Question 228 : <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small"></span></span><p class="wysiwyg-text-align-left">A sphere of radius $1 m$ encloses a charge of $5 \mu C$. Another charge of $-5 \mu C$ is placed inside the sphere. The net electric flux would be :<br/></p>
Question 229 :
What is the nature of Gaussian surface involved in Gauss law of electrostatic?
Question 230 :
The electric flux entering a closed surface is $2000 Vm$ and the flux coming out of the closed surface is $1000 Vm$. Then, the net charge enclosed inside the surface is :
Question 231 :
Which of the following statements is not true about Gauss's law?
Question 232 :
A spherical volume has a uniformly distributed charge density $2\times 10^{-4} Cm^{-3}$. The electric field at a point inside the volume at a distance 4.0 cm from the centre is :
Question 233 :
A particle with charge q is located inside a cubical gaussian surface. No other charges are nearby. If the particle can be moved to any point within the cube, what maximum value can the flux <span>through one face approach?</span>
Question 234 :
If the flux of the electric field through a closed surface is zero, then :
Question 235 :
In a certain region of space, there exists a uniform electric field of $2\times 10^{2} \hat {k} Vm^{-1}$. A rectangular coil of dimension $10\ cm\times 20\ cm$ is placed in $x - y$ plane. The electric flux through the coil is
Question 237 :
A point charge +q is placed at the centre of a cube of side L. The electric flux emerging from the cube is-
Question 238 :
The magnitude of the electric field as a function of the distanee r outside the ball is given by :
Question 240 :
The electric field in a region is $E = \displaystyle \frac{5\times 10^3 x}{2}\hat{i} \ NC^{-1} cm^{-1} $. The charge contained inside a cubical volume bounded by the surfaces $x = 0, x = 1, y = 0, y = 1, z = 0, z = 1$ is (where x, y, z are in cm) :
Question 241 :
Charges $Q_1$ and $Q_2$ lie inside and outside respectively of a closed surface S. Let E be the field at any point on S and $\phi$ be the flux of E over S
Question 242 :
The electric field in a region is radially outward with magnitude $E=\alpha r$. Calculate the charge contained in a sphere of radius R centered at the origin. Calculate the value of the charge if $\alpha =100 Vm^{-2}$ and R=0.30 m.
Question 243 :
A sphere of radius R carries charge such that its volume charge density is proportional to the square of the distance from the center. What is the ratio of the magnitude of the electric field at distance 2R from the center to the magnitude of the electric field at a distance of R/2 from the center?
Question 244 :
If the charge $+Q$ is now at the centre of a cube of side $2l$, what is the total flux emerging from all the six faces of the closed <span>surface? </span>
Question 245 :
Charges Q, 2Q and 4Q are uniformly distributed in three dielectric solid spheres 1,2 and 3 of radii R/2,R and 2R respectively. If magnitudes of the electric fields at point P at a distance R from the centre of sphere 1, 2 and 3 are $E_1$, $E_2$ and $E_3$ respectively, then :<br/>
Question 246 :
Which of the following are advantages of AC over DC ?
Question 247 :
What is the r.m.s. value of the current for A.C. current $I=100\cos(200t+45^o)A$.
Question 250 :
The source frequency for which a $5 \mu$ F capacitor has a reactance of 1000$\Omega $ is<br>
Question 251 :
The average e.m.f during the positive half cycle of an a.c. supply of peak value $E_{0}$ is:<br/>
Question 252 :
An alternating current is given by<br>$i={i}_{1}cos\omega t+{i}_{2}sin\omega t$<br>The rms is given by
Question 253 :
Match the following <br> Currents r.m.s values <br>(1) $ x_0 \, sin \, \omega t $ (i) $ x_0 $ <br>(2) $ x_0 \, sin \, \omega t \, cos \, \omega t $ (ii) $ \dfrac{x_0}{\sqrt{2}} $ <br>(3) $ x_0 \, sin \, \omega t \, + x_0 \, cos \, \omega t $ (iii) $ \dfrac{x_0}{2\sqrt{2}} $
Question 254 :
r.m.s. value of current $i=3+4\sin { (\omega t } +\dfrac { \pi }{ 3 }$) is:
Question 255 :
A 100 $\Omega $ resistor is connected to a 220 V, 50 Hz ac supply. The rms value of current in the circuit is then<br/>
Question 256 :
An A.C. is given by equation $I=I_{1} \cos \omega t+I_{2} \sin \omega t$. The r.m.s. value of current is given by<br/>
Question 257 :
If an AC main supply is given to be 220 V. The average emf during a positive half cycle will be
Question 258 :
When a coil rotated in magnetic field induced current in it :
Question 259 :
An AC current is given by $I=I_0+I_1\sin\omega t$ then the rms value will be.
Question 260 :
An ac is given by equation $ I = I)1\cos\omega t + I_2\sin\omega t$. The rms value of current is given by
Question 263 :
A beam of light consists of a bundle of light rays.
Question 266 :
Light of wavelength $\lambda$, strikes a photoelectric surface and electrons are ejected with an energy E. If E is to be increased to exactly twice its original value, the wavelength changes to $\lambda'$ where <span><br></span>
Question 267 :
In Hertz's experiment, the rods connected with an induction coil behave as.
Question 268 :
On reducing the wavelength of light incident on a metal, the velocity of emitted photoelectrons will become
Question 269 :
Minimum accelerating potential to be applied on an electron so that kinetic energy of electron equals energy of a quantum of wavelength 310 nm would be:
Question 270 :
$1.5mW$ of $400nm$ light is directed at a photoelectric cell. If $0.10$ percent of the incident photons produce photoelectrons, then the current in the cell is
Question 271 :
Assertion: Kinetic energy of photo electrons emitted by a photosensitive surface depends upon the intensity of incident photon.
Reason: The ejection of electrons from metallic surface is possible with frequency of incident photon below the threshold frequency.
Question 272 :
Two sources A and B have same power. The wavelength of radiation of A is $\lambda_{a}$ and that of B is $\lambda_{b}$. The number of photons emitted per second by A and B are $n_{a}$ & $n_{b}$ respectively, then,<br/>
Question 273 :
A small metal plate (work function$ =2eV$) is placed at a distance of $2m$ from a monochromatic light source of wavelength $4.8 \times 10^{-7}$ m and power $1.0$ watt. The light falls normally on the plate. The number of photons striking the metal plate per second per unit area will be<br/>
Question 274 :
In a photoelectric experiment, if the potential difference across the electrodes is equal to the stopping potential and the emitter plate is held at negative potential with respect to the collector plate mark the correct statement :<br>
Question 275 :
Light of intensity $I$ & frequency $\nu$ is incident perpendicularly on a metal surface of unit square area. The quantum efficiency, defined as the ratio of no. of ejected electrons to the no. of incident photons, is $x$ and the work function of the metal is $\phi$.Then:
Question 278 :
The incident photon involved in the photo-electric effect experiment ($\nu > \nu_o$)<br/>
Question 279 :
A strong argument for particle nature of cathode rays is that they
Question 280 :
How will you relate velocity of cathode rays to c, i<span>f ‘c' denotes the velocity of light?</span><br/>
Question 282 :
In interpreting Rutherford's experiments on the scattering of alpha particles by thin foils, one must examine what the known factors were, and what the experiment concluded. Which of the following are true in this context?
Question 284 :
Two parallel plates 5cm apart are connected to a 500 V D.C supply. Assuming that an electron starts from rest, its velocity after a nano second is<br/>
Question 285 :
An electron beam accelerated from rest through a potential difference of 5000 V in a vacuum is allowed to impinge on a surface normally. The incident current is 50 $\mu A$ and if the electrons come to rest on striking the surface, the force on it is<br>
Question 286 :
What should retarding potential difference be applied between electrodes of the photocell for the photocurrent to drop to zero?
Question 287 :
If a retarding potential of 1 V is applied between electrodes at what limiting wavelength $\lambda$ of light incident on the cathode will the photoelectric effect begin?
Question 288 :
Rutherford's experiments suggested that the size of the nucleus is about
Question 289 :
In Rutherford's alpha particle scattering experiment with thin gold foil, 8100 scintillations per minute are observed at an angle of 600. The number of scintillations per minute at an angle 1200 will be
Question 290 :
In an electron gun,the potential difference between the filament and plate is 3000V. What will be the velocity of electron-emitting from the gun?
Question 292 :
<span> If the series resistance decreases in an unloaded zener regulator, the zener current</span>
Question 297 :
The I V characteristics of solar cell is drawn in the fourth quadrant of the coordinate axes because
Question 298 :
Which of the following semi-conducting devices is used as voltage regulator?
Question 300 :
The anode of a thermionic diode is connected to the negative terminal of a battery and the cathode to its positive terminal.
Question 301 :
There photo dlodes $D_{1}, D_{2}$ and $D_{3}$ are made of semiconductor having band gap $2.5\ eV, 2\ eV$ and $3\ eV$ respectively. Which one will be able to detect light of wavelength $6000\ A^o$?
Question 302 :
An $n-p-n$ transistor has three leads $A,\ B$ and $C$. Connecting $B$ and $C$ by moist fingers, $A$ to the positive lead of an ammeter, and $C$ to the negative lead of the ammeter, one finds large deflection. Then, $A,\ B$ and $C$ refer respectively to :
Question 303 :
A zener diode voltage regulator operated in the range $120-180\ V$ produces a constant supply of $110\ V$ and $250\ mA$ to the load. If the maximum current is to be equally shared between the load and zener, then the values of series resistance ($\displaystyle { R }_{ S }$) and load resistance ($\displaystyle { R }_{ L }$) are:
Question 304 :
The peak voltage in the output of a half wave diode rectifier fed with a sinusoidal signal without filter is $15V.$ The $dc$ component of the output voltage is:
