Question 1 :
An electron enters a magnetic field whose direction is perpendicular to the velocity of the electron. Then
Question 2 :
If the current is doubled, the deflection is also doubled in
Question 3 :
The line on the earth surface joining the point where the field is horizontal, is called
Question 5 : A current <img style='object-fit:contain' width=6 height=20 src="https://storage.googleapis.com/teachmint/question_assets/NEET/5ea1bf2027ce131ff7c08ac8"> flows along the length of an infinitely long, straight, thin walled pipe. Then
Question 7 :
Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show
Question 8 :
The strength of the magnetic field in which the magnet of a vibration magnetometer is oscillating is increased 4 times its original value. The frequency of oscillation would then become
Question 9 : The velocity of two <img style='object-fit:contain' width=9 height=20 src="https://storage.googleapis.com/teachmint/question_assets/NEET/5ea1bfaa27ce131ff7c08d52"> -particles <img style='object-fit:contain' width=51 height=20 src="https://storage.googleapis.com/teachmint/question_assets/NEET/5ea1bf281ac76a0b860fe5a9"> in a uniform magnetic field is in the ratio of 1 : 3. They move in different circular orbits in the magnetic field. The ratio of radius of curvatures of their paths is
Question 10 :
A charged particle moving in a magnetic field experiences a resultant force
Question 11 :
A large magnet is broken into two pieces so that their lengths are in the 2:1. The pole strengths of the two pieces will have ratio
Question 12 :
A magnetic dipole is placed in a uniform magnetic field. The net magnetic force on the dipole
Question 13 : Three identical bars A, B and C are made of different magnetic
materials. When kept in a uniform magnetic field, the field
lines around them look as follows: <br> <img style='object-fit:contain' src="https://data-screenshots.sgp1.digitaloceanspaces.com/5d60fb149c699b6d4e700306.jpg" /> <br> Make the correspondence of these bars with their material being diamagnetic (D), ferromagnetic (F) and paramagnetic (P):
Question 14 :
A short magnet oscillates in an oscillation magnetometer with a time period of 0.10{tex} \mathrm { s } {/tex} where the earth's horizontal magnetic field is 24{tex} \mu T {/tex} . A downward current of 18{tex} \mathrm { A } {/tex} is established in a vertical wire placed 20{tex} \mathrm { cm } {/tex} east of the magnet. Find the new time period.
Question 15 :
A uniform electric field and a uniform magnetic field exist in a region in the same direction. An electron is projected with a velocity pointed in the same direction. Then the electron will
Question 16 :
A compass needle whose magnetic moment is {tex} 60 \mathrm { Am } ^ { 2 } , {/tex} is directed towards geographical north at any place experiencing moment of force of {tex} 1.2 \times 10 ^ { - 3 } \mathrm { Nm } {/tex} . At that place the horizontal component of earth field is 40{tex} \mathrm { micro } \mathrm { W } / \mathrm { m } ^ { 2 } {/tex} . What is the value of dip angle at that place?
Question 17 :
Torques {tex} \tau _ { 1 } {/tex} and {tex} \tau _ { 2 } {/tex} are required for a magnetic needle to remain perpendicular to the magnetic fields at two different places. The magnetic fields at those places are {tex} \mathrm { B } _ { 1 } {/tex} and {tex} \mathrm { B } _ { 2 } {/tex} respectively; then ratio {tex} \frac { \mathrm { B } _ { 1 } } { \mathrm { B } _ { 2 } } {/tex} is
Question 18 :
Alpha particles {tex} \left( \mathrm { m } = 6.7 \times 10 ^ { - 27 } \mathrm { kg } , \mathrm { q } = + 2 \mathrm { e } \right) {/tex} are accelerated from rest through a potential difference of 6.7 {tex} \mathrm { kV } {/tex}. Then, they enter a magnetic field {tex} \mathrm { B } = 0.2 \mathrm { T } {/tex} perpendicular to them direction of their motion. The radius of the path described by them is
Question 19 :
In sum and difference method vibration magnetometer, the time period is more if
Question 20 :
A loosely wound helix made of stiff wire is mounted vertically with the lower end just touching a dish of mercury. When a current from a battery is started in the coil through the mercury
Question 21 :
The angle of dip at a place is {tex} 37 ^ { \circ } {/tex} and the vertical component of the earth's magnetic field is {tex} 6 \times 10 ^ { - 5 } \mathrm { T } {/tex} . The earth's magnetic field at this place is {tex} \left( \tan 37 ^ { \circ } = 3 / 4 \right) {/tex}
Question 22 :
A coil in the shape of an equilateral triangle of side {tex} l {/tex} is suspended between the pole pieces of a permanent magnet such that {tex} \overrightarrow { \mathrm { B } } {/tex} is in the plane of the coil. If due to a current in the triangle a torque {tex} \tau {/tex} acts on it, the side {tex} l {/tex} of the triangle is
Question 23 :
A 10 eV electron is circulating in a plane at right angles to a uniform field at magnetic induction {tex} 10 ^ { - 4 } \mathrm { Wb } / \mathrm { m } ^ { 2 } ( = 1.0 {/tex} gauss). The orbital radius of the electron is
Question 24 : Two wires with currents 2{tex} \mathrm { A } {/tex} and {tex}1{/tex} A are enclosed in a circular loop. Another wire with current 3{tex} \mathrm { A } {/tex} is situated outside the loop as shown. The {tex} \oint \overrightarrow { \mathrm { B } } \cdot \mathrm { d } \vec { l } {/tex} around the loop is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5d60ef0de5db655bbf10a47d"><br>
Question 25 : The radius of the coil of a tangent galvanometer which has 10 turns is 0.1 m. The current required to produce a deflection of <img style='object-fit:contain' width='142' height='20' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5ea285ea3c680714de9a7d41"> is
Question 27 : {tex} A {/tex} and {tex} B {/tex} are {tex} t {/tex} wo conductors carrying a current {tex} i {/tex} in the same direction. {tex} x {/tex} and {tex} y {/tex} are two electron beams moving in the same direction. Then<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5d60eec9e5db655bbf10a453"><br>
Question 28 :
If a magnetic dipole of moment <b>M</b> situated in the direction of a magnetic field <b>B</b> is rotated by <b>180°</b> then the amount of work done is
Question 29 :
The magnetic field of earth at the equator is approximately {tex}4 \times 10 ^ { - 5 } \mathrm { T } {/tex} . The radius of earth is {tex} 6.4 \times 10 ^ { 6 } \mathrm { m } . {/tex} Then the dipole moment of the earth will be nearly of the order of:
Question 30 :
An alternating electric field, of frequency {tex} v , {/tex} is applied across {tex} \text { the dees (radius } = R ) {/tex} of a cyclotron that is being used to accelerate protons (mass = m ). The operating magnetic field (B) used in the cyclotron and the kinetic energy {tex} ( K ) {/tex} of the proton beam, produced by it, are given by:
Question 31 :
If in a circular coil {tex} A {/tex} of radius {tex} R , {/tex} current {tex} I {/tex} is flowing and in another coil {tex} B {/tex} of radius 2{tex} R {/tex} a current 2{tex} I {/tex} is flowing, then the ratio of the magnetic fields {tex} B _ { A } {/tex} and {tex} B _ { B } , {/tex} produced by them will be
Question 32 : A closed loop PQRS carrying a current is placed in a uniform magnetic field.<br>If the magnetic forces on segments PS, {tex} \mathrm { SR } , {/tex} and {tex} \mathrm { RQ } {/tex} are {tex} \mathrm { F } _ { 1 } , \mathrm { F } _ { 2 } {/tex} and {tex} \mathrm { F } _ { 3 } {/tex} respectively and are in the plane of the paper and along the directions shown, the force on the segment {tex} \mathrm { QP } {/tex} is<br><img style='object-fit:contain' src="https://data-screenshots.sgp1.digitaloceanspaces.com/5e9997f1ee93d464c7bbdbbf.jpg" />
Question 33 :
A charged particle moves through a magnetic field perpendicular to its direction. Then
Question 34 :
If the susceptibility of dia, para and ferro magnetic materials are {tex} \chi _ { \mathrm { d } } , \chi _ { \mathrm { p } } , \chi _ { \mathrm { f } } {/tex} respectively, then
Question 35 :
At a temperatur of {tex} \small 30 ^ { \circ } \mathrm { C } , {/tex} the susceptibility of a ferromagnetic material is found to be {tex} \small \chi {/tex} . Its susceptibility at {tex} \small 333 ^ { \circ } \mathrm { C } {/tex} is
Question 36 :
A charged particle with charge {tex} q {/tex} enters a region of constant, uniform and mutually orthogonal fields {tex}\vec E {/tex} and {tex} \vec { B } {/tex} with a velocity {tex} \vec { v } {/tex} perpendicular to both {tex} \vec { E } {/tex} and {tex} \vec { B } {/tex} , and comes out without any change in magnitude or direction of {tex} \vec { v } . {/tex} Then
Question 37 :
The earth's magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to <b>8 x 10<sup>22</sup> Am<sup>2</sup></b> , the value of earth's magnetic field near the equator is close to (radius of the earth {tex} = 6.4 \times 10 ^ { 6 } \mathrm { m } {/tex} )
Question 38 : A square loop, carrying a steady current I, is placed in a horizontal plane near a long straight conductor carrying a steady current {tex} I_ { 1 } {/tex} at a distance d from the conductor as shown in figure. The loop will experience<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5d60ef63e5db655bbf10a4b4"><br>
Question 39 :
Which of the following statements is true about the flow of electrons in an electric circuit?
Question 40 :
The electron drift speed is small and the charge of the electron is also small but still, we obtain large current in a conductor. This is due to
Question 43 :
The work done in bringing a unit positive charge from infinite distance to a point at distance x from a positive charge Q is W. Then the potential $\phi$ at that point is:
Question 44 :
In a CRO the acceleration of electrons is controlled by changing .................. between the cathode and anode.<br>
Question 45 :
Assertion: A current flows in a conductor only when there is an electric field within the conductor.
Reason: The drift velocity of electron in presence of electric field decreases.
Question 46 :
The work done is carrying a charge q once round a circle of radius r with a charge q at the center is?
Question 47 :
The kinetic energy of an electron, which is accelerated in the potential difference of $100\ V$, is
Question 49 : <span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small"></span></span><p class="wysiwyg-text-align-left">There is 10 units of charge at the centre of a circle of radius 10m. The work done in moving 1 unit of charge around the circle once is:</p>
Question 50 :
The electric potential (in volt) a region given by<br>$V = 6 x - 8 x y ^ { 2 } - 8 y + 6 y z - 4 x ^ { 2 }$ Then electric force acting on a point charge of 2c placed at the origin will be
Question 52 :
A resistor connected to a battery is heated due to current through it. Which of the following quantity does not vary?<br>
Question 54 :
Two identical parallel plate capacitors are connected in series and then joined with a battery of $100\ V$. A sheet of dielectric constant $4.0$ is inserted between the plates of second capacitor. The potential difference across the capacitors will be respectively.
Question 56 :
The quantity $X = \dfrac {\epsilon_{0}LV}{t} : \epsilon_{0}$ is the permittivity of free space, $L$ is length, $V$ is potential difference and $t$ is time. The dimensions of $X$ are same as that of
Question 58 :
In a non-linear electric field, a charged particle returns to its initial point sometime after it is released in the field. The work done by the field is given by
Question 59 :
If the work is to be done to take $3$ C electric charge from one point to another point is $15 J$, what will be the potential difference between these two points ?
Question 60 :
In a circuit, 5C of charge is passed through a battery in 3 hours. The plates of the battery are maintained at the potential difference of 12 V. Then, the amount of work done by a battery is:
Question 61 :
A cloud is at a potential of $8\times 10^{9}\ V$ relative to the ground. A charge of $40\ C$ is transferred in a lightning stroke between the cloud and the earth. The energy released is:
Question 62 :
Two wires of the same material have lengths 3 cm and 5 cm and radii 1 mm and 3 mm respectively. They are connected in series across a battery of 16 V. The p.d. across the shorter wire is
Question 63 :
Assertion: If a point charge is rotated in a circle around another charge at the center of circle, the work done by the electric field will be zero.
Reason: Work done is equal to dot product of force and displacement.
Question 64 :
Heat flows radially outward through a spherical shell of outside radius $R_{2}$ and inner radius $R_{1}$. The temperature of inner surface is $\Theta _{1}$ and that outer is $\Theta _{2}$. At what radial distance fro m center of shell the temperature is just half way between $\Theta _{1}$ and $\Theta _{2}$
Question 65 :
Two points P and Q are maintained at potentials of of $10V$ and $-4V$ respectively. The work done in moving $100$ electrons from P to Q is proportional to
Question 66 :
A charge is moved from a point A to point B. The work done to move unit charge during this process is called.<br>
Question 67 :
Given that $E = ((3x^2<br><br> + y) \hat i + x \hat y) kV/m$, find the work done in moving a $- 2 \mu C$ charge from $(0, 5, 0)$ to $(2, -1 , 0)$ by taking the path :<br>$y=5-3x$
Question 68 :
Assertion: STATEMENT-1 : The current density $\vec{J}$ at any point in ohmic resistor is in direction of electric field $\vec{E}$ at that point.
Reason: STATEMENT-2 : A point charge when released from rest in a region having only electrostatic field always moves along electric lines of force.
Question 69 :
The current density across a cylindrical conductor of radius $R$ varies according to the equation $J = J_0\left(1-\displaystyle\frac{r}{R}\right)$, where $r$ is the distance from the axis. Thus the current density is a maximum $J_0$ at the axis $r=0$ and decreases linearly to zero at the surface $r=R$. Calculate the current in terms of $J_0$ and the conductors cross sectional area is $A = \pi R^2$.<br>
Question 70 :
A parallel plate condenser has conducting plates of radius $12cm$ seperated by a distance of $5mm$. It is charged with a constant charging current of $0.16A$. the rate at which the potential difference between the plates change is:
Question 71 :
A charge of $10$ C is brought from infinity to a point near a charged body and in this process, $200$ J of work is done.  Calculate the electric potential at that point near the charged body
Question 73 :
<span>How much work would be required to move a proton from the negative to the positive plate?</span>
Question 74 :
A potential difference of $2.5$V is applied across the faces of a germanium crystal plate. The face area of the crystal is $1$ $cm^2$ and its thickness is $1.0$ mm. The free electron concentration in germanium is $2\times 10^{19} m^{-3}$ and the electron and holes mobilities are $0.33 m^2/V$ and $0.17m^2/V$ respectively. The current across the plate will be?
Question 75 :
Find the current produced when $20,000$ alpha-particles per second are passing through a straight tube of certain radius.
Question 76 :
A 1-meter length 22 gauge of copper wire has a current of 1 mA passing through it $1.7\times10^8m$<span class="MathJax"><span class="MJX_Assistive_MathML">=1.7108m</span></span> in this wire.
Question 77 :
A point-charge of $6.0\times 10^{-8}$ C is situated at the coordinate origin. How much work will be done in taking an electron from the point $x=3$m to $x=6$m?
