Question 1 :
Five cells each of internal resistance $ 0.2 \Omega $ and emf $ 2 V$ are connected in series with a resistance of $ 4\Omega $.The current through the external resistance is
Question 2 :
The resistance of a carbon filament at $0^oC$ is 104$\Omega$. It is connected in series with an iron wire. The temperature coefficients of resistivity of carbon and iron are $- 0.0003$ and $0.0052$ per $^oC$ respectively. What must be the resistance of iron wire so that the combined resistance does not change with temperature?
Question 3 :
A counter consists of a cylindrical cathode of radius $1 cm$ and an anode wire of radius $0.01 cm$ which is placed along the axis of the cathode. A voltage of $2.3 kV$  is applied between the cathode and anode. The electric field on the anode surface must be :<br/>
Question 6 :
A proton is rotating along a circular path with kinetic energy K in a uniform magnetic field B.If the magnetic field is made four times, the kinetic energy of rotation of proton is<br/><br/>
Question 7 :
An electron moves with a velocity $1\times {10}^{3}m/s$ in a magnetic field of induction $0.3T$ at an angle ${30}^{o}$. If $\cfrac{e}{m}$ of electrons $1.76\times {10}^{11}C/kg$, the radius of the path is nearly
Question 8 :
If the speed of the charged particle moving through the magnetic field is increased , then the radius of curvature of trajectory will :
Question 9 : <p class="wysiwyg-text-align-left"><span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">If 3 capacitors of values 1, 2 and $3 \mu F$ are available. The maximum and minimum values of capacitance one can obtain by different combinations of the three capacitors together are respectively:<br/></p>
Question 10 :
A fully charged capacitor has a capacitance '$C$'. It is discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat capacity '$s$' and mass '$m$'. If the temperature of the block is raised $'\Delta T'$, the potential difference '$V$' across the capacitance is :<br/>
Question 12 :
A thick strip of copper is mounted as a compound pendulum about O.If it is made to swing through a uniform magnetic field B normal to the plane of the strip then (neglecting air resistance) it is found that
Question 13 :
A rectangular loop of sides $a$ and $b$ is placed in $x-y$ plane. A uniform but time varying magnetic field of strength $\vec { B } =20t\hat { i } +10{ t }^{ 2 }\hat { j } +50\hat { k } $ is present in the region. The magnitude of induced emf in the loop at time $t$ is :<br/>
Question 14 :
Which of the following is the right derivation for Ampere-Maxwell law?
Question 15 :
The electric field of a plane electromagnetic wave is given by<br>$\overrightarrow { y }=E_0 \hat{i} cos(kz)(\omega t)$<br>The corresponding magnetic field $\overrightarrow { B }$ is then given by:
Question 16 :
In an electromagnetic wave, the electric and magnetic fields are $100 Vm ^{-1}$and $0.265 Am$ maximum energy flow is
Question 17 :
In Young's double slit experiment a minima is observed when path difference between the interfering beam is
Question 18 :
From Brewster's law, except for polished metallic surface, the polarising angle
Question 19 :
Assertion: In Young's interference experiment fringes become brighter if one of the slits is covered by cellophone paper.
Reason: The intensity of light emerging from the slit increases and the two interfering beams have unequal intensities.
Question 20 :
A resonant circuit has a lower critical frequency of $7 kHz$ and an upper critical frequency of $13 kHz$. The bandwidth of the circuit is<br/>
Question 21 :
In an L-R circuit, the voltage is given by $V$ as $283 sin 314t$. The current is found tc be $4 \, sin \left ( 314t-\dfrac {\pi}{4} \right )$Calculate the resistance of the circuit. 
Question 22 :
Identify the wrong statement in the following. Coulomb's law correctly describes the electric force that
Question 23 :
A solid sphere of radius $R$ has a charge $Q$ distributed in its volume with a charge density $\rho = kr^{a}$, where $k$ and $a$ are constants and $r$ is the distance from its centre. If the electric field at $r = \dfrac {R}{2}$ is $\dfrac {1}{8}$ times that at $r = R$, the value of $a$ is
Question 24 :
If the three particles having their charges in the ratio of $1 : 3 : 5$ produce same spot on the screen in Thomson's experiment, then their masses will be in the ratio of
Question 25 :
When a hydrogen atom is raised from ground energy level to excited energy level, then
Question 26 :
By which optical phenomena the splitting of white light into seven constituent colours occur?<br>
Question 27 :
From a point source a light falls on a spherical glass surface $(\mu = 1.5 \, and \, radius \, of \, curvature\, = 10 cm)$. The distance between point source and glass surface is 50 cm . The position of image is
Question 29 :
Shining light of wavelength $\lambda$ and intensity $I$ is incident on a surface $S$ produces photoelectrons at a rate $R$ with maximum kinetic energy $E$. Consider the following statements from the effect of changing one parameter at a time<br>Doubling $I$ always doubles $R$<br>Doubling $I$ does not change $E$ at all<br>Making $\lambda$ half always makes $E$ more than double<br>
Question 30 :
In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
