Quiz - physics - Moving Charges and Magnetism-PYQ

Q1. A metallic rod of mass per unit length 0.5 kg m$^{-1}$ is lying horizontally on a smooth inclined plane which makes an angle of 30° with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is Source: orcusprep.in

NEET 2018

medium

7.14 A

5.98 A

14.76 A

11.32 A

Q2. When a proton is released from rest in a room, it starts with an initial acceleration $a_0$ towards west. When it is projected towards north with a speed $v_0$ it moves with an initial acceleration $3a_0$ toward west. The electric and magnetic fields in the room are Source: orcusprep.in

NEET 2013

hard

$\frac{ma_0}{e}$ east, $\frac{3ma_0}{ev_0}$ up

$\frac{ma_0}{e}$ east, $\frac{3ma_0}{ev_0}$ down

$\frac{ma_0}{e}$ west, $\frac{2ma_0}{ev_0}$ up

$\frac{ma_0}{e}$ west, $\frac{2ma_0}{ev_0}$ down

Q3. A long straight wire carries a certain current and produces a magnetic field $2 \times 10^{-4}$ Wb m$^{-2}$ at a perpendicular distance of 5 cm from the wire. An electron situated at 5 cm from the wire moves with a velocity $10^7$ m/s towards the wire along perpendicular to it. The force experienced by the electron will be (charge on electron $1.6 \times 10^{-19}$ C) Source: orcusprep.in

NEET 2013

medium

3.2 N

3.2 $\times 10^{-16}$ N

1.6 $\times 10^{-16}$ N

zero

Q4. A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron Source: orcusprep.in

AIPMT 2011

easy

will turn towards right of direction of motion

speed will decrease

speed will increase

will turn towards left of direction of motion

Q5. The magnetic force acting on a charged particle of charge $-2 \mu C$ in a magnetic field of 2 T acting in y direction, when the particle velocity is $(2\hat{i} + 3\hat{j}) \times 10^6$ m/s is Source: orcusprep.in

AIPMT 2009

medium

4 N in z direction

8 N in y direction

8 N in z direction

8 N in -z direction

Q6. When a charged particle moving with velocity $\vec{v}$ is subjected to a magnetic field of induction $\vec{B}$, the force on it is non-zero. This implies that Source: orcusprep.in

AIPMT 2006

easy

angle between $\vec{v}$ and $\vec{B}$ is either zero or 180°

angle between $\vec{v}$ and $\vec{B}$ is necessarily 90°

angle between $\vec{v}$ and $\vec{B}$ can have any value other than 90°

angle between $\vec{v}$ and $\vec{B}$ can have any value other than zero and 180°

Q7. A very long straight wire carries a current I. At the instant when a charge +Q at point P has velocity $\vec{v}$, as shown, the force on the charge is Source: orcusprep.in

AIPMT 2005

medium

along Oy

opposite to Oy

along Ox

opposite to Ox

Q8. A charge q moves in a region where electric field and magnetic field both exist, then force on it is Source: orcusprep.in

AIPMT 2002

easy

$q(\vec{v} \times \vec{B})$

$q\vec{E} + q(\vec{v} \times \vec{B})$

$q\vec{E} + q(\vec{B} \times \vec{v})$

$q\vec{B} + q(\vec{v} \times \vec{E})$

Q9. Tesla is the unit of Source: orcusprep.in

AIPMT 1997

easy

electric field

magnetic field

electric flux

magnetic flux

Q10. A charge moving with velocity v in X-direction is subjected to a field of magnetic induction in negative X-direction. As a result, the charge will Source: orcusprep.in

AIPMT 1993

easy

remain unaffected

start moving in a circular path Y-Z plane

retard along X-axis

moving along a helical path around X-axis

Q11. A straight wire of length 0.5 metre and carrying a current of 1.2 ampere is placed in uniform magnetic field of induction 2 tesla. The magnetic field is perpendicular to the length of the wire. The force on the wire is Source: orcusprep.in

AIPMT 1992

easy

2.4 N

1.2 N

3.0 N

2.0 N

Q12. Ionized hydrogen atoms and α-particles with same momenta enters perpendicular to a constant magnetic field, B. The ratio of their radii of their paths $r_H : r_α$ will be Source: orcusprep.in

NEET 2019

medium

1 : 4

2 : 1

1 : 2

4 : 1

Q13. A proton and an alpha particle both enter a region of uniform magnetic field B, moving at right angles to the field B. If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is 1 MeV, the energy acquired by the alpha particle will be Source: orcusprep.in

AIPMT 2015

hard

1.5 MeV

1 MeV

4 MeV

0.5 MeV

Q14. A proton carrying 1 MeV kinetic energy is moving in a circular path of radius R in uniform magnetic field. What should be the energy of an α-particle to describe a circle of same radius in the same field? Source: orcusprep.in

AIPMT 2012

hard

2 MeV

1 MeV

0.5 MeV

4 MeV

Q15. Under the influence of a uniform magnetic field, a charged particle moves with a constant speed v in a circle of radius R. The time period of rotation of the particle Source: orcusprep.in

AIPMT 2009

medium

depends on R and not on v

is independent of both v and R

depends on both v and R

depends on v and not on R

Q16. A particle of mass m, charge Q and kinetic energy T enters in a transverse uniform magnetic field of induction $\vec{B}$. After 3 seconds the kinetic energy of the particle will be Source: orcusprep.in

AIPMT 2008

medium

T

4T

3T

2T

Q17. A charged particle moves through a magnetic field in a direction perpendicular to it. Then the Source: orcusprep.in

AIPMT 2003

easy

speed of the particle remains unchanged

direction of the particle remains unchanged

acceleration remains unchanged

velocity remains unchanged

Q18. An electron having mass m and kinetic energy E enter in uniform magnetic field B perpendicularly, then its frequency will be Source: orcusprep.in

AIPMT 2001

medium

$\frac{eE}{qvB}$

$\frac{2\pi m}{eB}$

$\frac{eB}{2\pi m}$

$\frac{2m}{eBE}$

Q19. A charge having $\frac{e}{m}$ equal to $10^8$ C/kg and with velocity $3 \times 10^5$ m/s enters into a uniform magnetic field B = 0.3 tesla at an angle 30° with direction of field. The radius of curvature will be Source: orcusprep.in

AIPMT 1999

medium

0.01 cm

0.5 cm

1 cm

2 cm

Q20. A positively charged particle moving due East enters a region of uniform magnetic field directed vertically upwards. This particle will Source: orcusprep.in

AIPMT 1997

medium

move in a circular path with a decreased speed

move in a circular path with a uniform speed

get deflected in vertically upward direction

move in circular path with an increased speed

Q21. A 10 eV electron is circulating in a plane at right angles to a uniform field at magnetic induction $10^{-4}$ Wb/m² (= 1.0 gauss), the orbital radius of electron is Source: orcusprep.in

AIPMT 1996

hard

11 cm

18 cm

12 cm

16 cm

Q22. A uniform magnetic field acts right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of electrons is doubled, then the radius of the circular path will be Source: orcusprep.in

AIPMT 1991

easy

2.0 cm

0.5 cm

4.0 cm

1.0 cm

Q23. A deuteron of kinetic energy 50 keV is describing a circular orbit of radius 0.5 metre in a plane perpendicular to magnetic field B. The kinetic energy of the proton that describes a circular orbit of radius 0.5 metre in the same plane with the same B is Source: orcusprep.in

AIPMT 1991

hard

25 keV

50 keV

200 keV

100 keV

Q24. An alternating electric field, of frequency ν, is applied across the dees (radius = R) 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 (K) of the proton beam, produced by it, are given by Source: orcusprep.in

AIPMT 2012

hard

$B = \frac{mν}{e}$, $K = 2π^2mν^2R^2$

$B = \frac{2πmν}{e}$, $K = 2π^2mν^2R^2$

$B = \frac{2πmν}{e}$, $K = π^2mν^2R^2$

$B = \frac{mν}{e}$, $K = π^2mν^2R^2$

Q25. A particle having a mass of $10^{-2}$ kg carries a charge of $5 × 10^{-8}$ C. The particle is given an initial horizontal velocity of $10^5$ m/s in the presence of electric field $\vec{E}$ and magnetic field $\vec{B}$. To keep the particle moving in a horizontal direction, it is necessary that Source: orcusprep.in

AIPMT 2010

hard

(1) and (3)

(3) and (4)

(2) and (3)

(2) and (4)

Q26. A beam of electron passes undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons move Source: orcusprep.in

AIPMT 2007

medium

in a circular orbit

along a parabolic path

along a straight line

in an elliptical orbit

Q27. In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential V and then made to describe semicircular paths of radius R using a magnetic field B. If V and B are kept constant, the ratio $\frac{\text{charge on the ion}}{\text{mass of the ion}}$ will be proportional to Source: orcusprep.in

AIPMT 2007

medium

$1/R^2$

$R^2$

$R$

$1/R$

Q28. In Thomson mass spectrograph $\vec{E} \perp \vec{B}$ then the velocity of electron beam will be Source: orcusprep.in

AIPMT 2001

medium

$\frac{|\vec{E}|}{|\vec{B}|}$

$\vec{E} × \vec{B}$

$\frac{|\vec{B}|}{|\vec{E}|}$

$\frac{E^2}{B^2}$

Q29. A beam of electrons is moving with constant velocity in a region having electric and magnetic fields of strength 20 V/m and 0.5 T at right angles to the direction of motion of the electrons. What is the velocity of the electrons? Source: orcusprep.in

AIPMT 1996

easy

8 m/s

5.5 m/s

20 m/s

40 m/s

Q30. The magnetic field $d\vec{B}$ due to a small current element $d\vec{l}$ at a distance $\vec{r}$ and element carrying current i is Source: orcusprep.in

AIPMT 1996

medium

$d\vec{B} = \frac{\mu_0}{4\pi} \frac{i(d\vec{l} × \vec{r})}{r^2}$

$d\vec{B} = \frac{\mu_0}{4\pi} \frac{i(d\vec{l} × \vec{r})}{r^3}$

$d\vec{B} = \frac{\mu_0}{4\pi} i(d\vec{l} × \vec{r})$

$d\vec{B} = \frac{\mu_0}{2\pi} \frac{i(d\vec{l} × \vec{r})}{r^2}$

Q31. A straight conductor carrying current i splits into two parts as shown in the figure. The radius of the circular loop is R. The total magnetic field at the centre P at the loop is Source: orcusprep.in

NEET 2019

hard

Zero

$\frac{3\mu_0 i}{32R}$, outward

$\frac{3\mu_0 i}{32R}$, inward

$\frac{\mu_0 i}{2R}$, inward

Q32. A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of n turns will be Source: orcusprep.in

NEET 2016

medium

nB

n²B

2nB

2n²B

Q33. A wire carrying current I has the shape as shown in adjoining figure. Linear parts of the wire are very long and parallel to X-axis while semicircular portion of radius R is lying in Y-Z plane. Magnetic field at point O is Source: orcusprep.in

AIPMT 2015

hard

$\vec{B} = \frac{\mu_0 I}{4R}(-\hat{i} + \frac{\pi}{2}\hat{k})$

$\vec{B} = \frac{\mu_0 I}{4R}(\frac{\pi}{2}\hat{i} - \hat{k})$

$\vec{B} = \frac{\mu_0 I}{4R}(\hat{i} + \frac{\pi}{2}\hat{k})$

$\vec{B} = \frac{\mu_0 I}{4R}(-\hat{i} - \frac{\pi}{2}\hat{k})$

Q34. Two similar coils of radius R are lying concentrically with their planes at right angles to each other. The currents flowing in them are I and 2I, respectively. The resultant magnetic field induction at the centre will be Source: orcusprep.in

AIPMT 2012

medium

$\frac{\sqrt{5}\mu_0 I}{2R}$

$\frac{\sqrt{5}\mu_0 I}{R}$

$\frac{\mu_0 I}{2R}$

$\frac{\mu_0 I}{R}$

Q35. Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency f Hz. The magnitude of magnetic induction at the center of the ring is Source: orcusprep.in

AIPMT 2011

medium

$\frac{\mu_0 qf}{2R}$

$\frac{\mu_0 qf}{2\pi R}$

$\frac{\mu_0 q}{2fR}$

$\frac{\mu_0 q}{2\pi fR}$

Q36. A current loop consists of two identical semicircular parts each of radius R, one lying in the x-y plane and the other in x-z plane. If the current in the loop is i. The resultant magnetic field due to the two semicircular parts at their common centre is Source: orcusprep.in

AIPMT 2010

hard

$\frac{\mu_0 i}{2\sqrt{2}R}$

$\frac{\mu_0 i}{2R}$

$\frac{\mu_0 i}{4R}$

$\frac{\mu_0 i}{\sqrt{2}R}$

Q37. Two circular coils 1 and 2 are made from the same wire but the radius of the 1st coil is twice that of the 2nd coil. What potential difference in volts should be applied across them so that the magnetic field at their centres is the same? Source: orcusprep.in

AIPMT 2006

hard

4

3

2

6

Q38. An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional to Source: orcusprep.in

AIPMT 2005

medium

$\sqrt{B/v}$

$B/v$

$\sqrt{v/B}$

$v/B$

Q39. The magnetic field of given length of wire for single turn coil at its centre is B then its value for two turns coil for the same wire is Source: orcusprep.in

AIPMT 2002

easy

$B/4$

$B/2$

$4B$

$2B$

Q40. Magnetic field due to 0.1 A current flowing through a circular coil of radius 0.1 m and 1000 turns at the centre of the coil is Source: orcusprep.in

AIPMT 1999

easy

$6.28 \times 10^{-4}$ T

$4.31 \times 10^{-2}$ T

$2 \times 10^{-1}$ T

$9.81 \times 10^{-4}$ T

Q41. Magnetic field intensity at the centre of the coil of 50 turns, radius 0.5 m and carrying a current of 2 A, is Source: orcusprep.in

AIPMT 1999

easy

$1.25 \times 10^{-4}$ T

$3 \times 10^{-5}$ T

$0.5 \times 10^{-5}$ T

$4 \times 10^{6}$ T

Q42. A coil of one turn is made of a wire of certain length and then from the same length a coil of two turns is made. If the same current is passed in both the cases, then the ratio of the magnetic inductions at their centres will be Source: orcusprep.in

AIPMT 1998

medium

$1 : 4$

$4 : 1$

$1 : 2$

$2 : 1$

Q43. A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field, B with the distance, d from the centre of the conductor, is correctly represented by the figure Source: orcusprep.in

NEET 2019

medium

(Graph D) showing B ∝ r inside and B ∝ 1/r outside

Graph showing constant B inside and outside

Graph showing B ∝ r² inside and constant outside

Graph showing B ∝ 1/r inside and constant outside

Q44. A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross-section. The ratio of the magnetic fields B and B′, at radial distances a/2 and 2a respectively, from the axis of the wire is Source: orcusprep.in

NEET 2016

medium

1

4

$\frac{1}{4}$

$\frac{1}{2}$

Q45. Two identical long conducting wires AOB and COD are placed at right angle to each other, with one above other such that O is their common point for the two. The wires carry I₁ and I₂ currents, respectively. Point P is lying at distance d from O along a direction perpendicular to the plane containing the wires. The magnetic field at the point P will be Source: orcusprep.in

AIPMT 2014

hard

$\frac{\mu_0}{\pi d}\sqrt{I_1^2 + I_2^2}$

$\frac{\mu_0}{2\pi d}(I_1 + I_2)$

$\frac{\mu_0}{2\pi d}(I_1^2 - I_2^2)$

$\frac{\mu_0}{2\pi d}(I_1^2 + I_2^2)^{1/2}$

Q46. The magnetic field at centre, P will be Source: orcusprep.in

AIPMT 2000

medium

$\frac{\mu_0}{4\pi}$

$\frac{\mu_0}{\pi}$

$\frac{\mu_0}{2\pi}$

$4\mu_0\pi$

Q47. A straight wire of diameter 0.5 mm carrying a current of 1 A is replaced by the another wire of 1 mm diameter carrying the same current. The strength of the magnetic field far away is Source: orcusprep.in

AIPMT 1999

easy

same as the earlier value

one-quarter of the earlier value

one-half of the earlier value

twice the earlier value

Q48. If a long hollow copper pipe carries a current, then produced magnetic field will be Source: orcusprep.in

AIPMT 1999

easy

outside the pipe only

both inside and outside the pipe

inside the pipe only

neither inside nor outside the pipe

Q49. Two equal electric currents are flowing perpendicular to each other as shown in the figure. AB and CD are perpendicular to each other and symmetrically placed with respect to the currents. Where do we expect the resultant magnetic field to be zero? Source: orcusprep.in

AIPMT 1996

medium

On both AB and CD

On CD

On AB

On both OD and BO

Q50. The magnetic field at a distance r from a long wire carrying current i is 0.4 tesla. The magnetic field at a distance 2r is Source: orcusprep.in

AIPMT 1992

easy

0.2 tesla

0.8 tesla

0.1 tesla

1.6 tesla

Q51. The magnetic induction at a point P which is at the distance of 4 cm from a long current carrying wire is $10^{-3}$ T. The field of induction at a distance 12 cm from the current will be Source: orcusprep.in

AIPMT 1990

easy

$3.33 \times 10^{-4}$ T

$1.11 \times 10^{-4}$ T

$33 \times 10^{-3}$ T

$9 \times 10^{-3}$ T

Q52. A long solenoid of 50 cm length having 100 turns carries a current of 2.5 A. The magnetic field at the centre of the solenoid is ($\mu_0 = 4\pi × 10^{-7}$ T m A$^{-1}$) Source: orcusprep.in

NEET 2020

easy

$6.28 × 10^{-4}$ T

$3.14 × 10^{-4}$ T

$6.28 × 10^{-5}$ T

$3.14 × 10^{-5}$ T

Q53. Two toroids 1 and 2 have total number of turns 200 and 100 respectively with average radii 40 cm and 20 cm respectively. If they carry same current i, the ratio of the magnetic fields along the two loops is Source: orcusprep.in

NEET 2019

medium

1 : 1

4 : 1

2 : 1

1 : 2

Q54. A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is Source: orcusprep.in

AIPMT 2003

easy

B

B/2

2B

4B

Q55. An arrangement of three parallel straight wires placed perpendicular to plane of paper carrying same current "I" along the same direction as shown in figure. Magnitude of force per unit length on the middle wire "B" is given by Source: orcusprep.in

NEET 2017

medium

$\frac{\mu_0 I^2}{\sqrt{2}\pi d}$

$\frac{\sqrt{2}\mu_0 I^2}{\pi d}$

$\frac{\mu_0 I^2}{2\pi d}$

$\frac{\sqrt{2}\mu_0 I^2}{2\pi d}$

Q56. A square loop ABCD carrying a current i, is placed near and coplanar with a long straight conductor XY carrying a current I, the net force on the loop will be Source: orcusprep.in

NEET 2016

hard

$\frac{2\mu_0 Ii}{3\pi}$

$\frac{\mu_0 Ii}{2\pi}$

$\frac{2\mu_0 IiL}{3\pi}$

$\frac{\mu_0 IiL}{2\pi}$

Q57. A square loop, carrying a steady current I, is placed in a horizontal plane near a long straight conductor carrying a steady current I₁ at a distance d from the conductor as shown in figure. The loop will experience Source: orcusprep.in

AIPMT 2011

medium

a net attractive force towards the conductor

a net repulsive force away from the conductor

a net torque acting upward perpendicular to the horizontal plane

a net torque acting downward normal to the horizontal plane

Q58. Two long parallel wires are at a distance of 1 metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is Source: orcusprep.in

AIPMT 1998

easy

$2 × 10^{-7}$ N/m

$5 × 10^{-8}$ N/m

$2 × 10^{-8}$ N/m

$10^{-7}$ N/m

Q59. Two parallel wires in free space are 10 cm apart and each carries a current of 10 A in the same direction. The force exerted by one wire on the other, per metre length is Source: orcusprep.in

AIPMT 1997

easy

$2 × 10^{-4}$ N, attractive

$2 × 10^{-7}$ N, repulsive

$2 × 10^{-4}$ N, repulsive

$2 × 10^{-7}$ N, attractive

Q60. A rectangular coil of length 0.12 m and width 0.1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2 Weber/m². The coil carries a current of 2 A. If the plane of the coil is inclined at an angle of 30° with the direction of the field, the torque required to keep the coil in stable equilibrium will be Source: orcusprep.in

AIPMT 2015

medium

0.20 N m

0.24 N m

0.12 N m

0.15 N m

Q61. A current loop in a magnetic field Source: orcusprep.in

NEET 2013

easy

can be in equilibrium in two orientations, one stable while the other is unstable

can be in equilibrium in two orientations, both the equilibrium states are unstable

experiences a torque whether the field is uniform or non uniform in all orientations

can be in equilibrium in one orientation

Q62. A circular coil ABCD carrying a current "i" is placed in a uniform magnetic field. If the magnetic force on the segment AB is $\vec{F}$, the force on the remaining segment BCDA is Source: orcusprep.in

NEET 2013

medium

$-\vec{F}$

$3\vec{F}$

$-3\vec{F}$

$\vec{F}$

Q63. A current carrying closed loop in the form of a right angle isosceles triangle ABC is placed in a uniform magnetic field acting along AB. If the magnetic force on the arm BC is $\vec{F}$ the force on the arm AC is Source: orcusprep.in

AIPMT 2011

hard

$-\vec{F}$

$-\sqrt{2}\vec{F}$

$\vec{F}$

$\sqrt{2}\vec{F}$

Q64. A square current carrying loop is suspended in a uniform magnetic field acting in the plane of the loop. If the force on one arm of the loop is $\vec{F}$ the net force on the remaining three arms of the loop is Source: orcusprep.in

AIPMT 2010

medium

$-\vec{F}$

$3\vec{F}$

$-3\vec{F}$

$\vec{F}$

Q65. A closed loop PQRS carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments PS, SR and RQ are F₁, F₂ and F₃ respectively and are in the plane of the paper and along the directions shown, the force on the segment QP is Source: orcusprep.in

AIPMT 2008

hard

$\sqrt{(F_3 - F_1)^2 + F_2^2}$

$F_3 - F_1 + F_2$

$F_3 - F_1 - F_2$

$\sqrt{(F_3 - F_1)^2 - F_2^2}$

Q66. A charged particle (charge q) is moving in a circle of radius R with uniform speed v. The associated magnetic moment μ is given by Source: orcusprep.in

AIPMT 2007

medium

$\frac{qvR}{2}$

$qvR^2$

$\frac{qvR^2}{2}$

$qvR$

Q67. A coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanent magnet such that $\vec{B}$ is in plane of the coil. If due to a current i in the triangle a torque τ acts on it, the side l of the triangle is Source: orcusprep.in

AIPMT 2005

hard

$\frac{2}{\sqrt{3}}\sqrt{\frac{\tau}{Bi}}$

$\frac{2}{\sqrt{3}}\frac{\tau}{Bi}$

$2\sqrt{\frac{\tau}{3Bi}}$

$\frac{1}{\sqrt{3}}\frac{\tau}{Bi}$

Q68. If number of turns, area and current through a coil is given by n, A and i respectively then its magnetic moment will be Source: orcusprep.in

AIPMT 2001

easy

niA

$n^2iA$

$niA^2$

$\frac{ni}{A}$

Q69. A circular loop of area 0.01 m² carrying a current of 10 A, is held perpendicular to a magnetic field of intensity 0.1 T. The torque acting on the loop is Source: orcusprep.in

AIPMT 1994

easy

zero

0.001 N m

0.8 N m

0.01 N m

Q70. A coil carrying electric current is placed in uniform magnetic field Source: orcusprep.in

AIPMT 1993

easy

torque is formed

e.m.f is induced

both (a) and (b) are correct

none of these

Q71. A current carrying coil is subjected to a uniform magnetic field. The coil will orient so that its plane becomes Source: orcusprep.in

AIPMT 1988

easy

perpendicular to magnetic field

inclined at 45° to the magnetic field

inclined at any arbitrary angle to the magnetic field

parallel to the magnetic field

Q72. Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is Source: orcusprep.in

NEET 2018

medium

250 Ω

40 Ω

25 Ω

500 Ω

Q73. In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be Source: orcusprep.in

AIPMT 2014

medium

$\frac{G}{500}$

$\frac{1}{499}G$

$\frac{499}{500}G$

$\frac{500}{499}G$

Q74. A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunt will be Source: orcusprep.in

AIPMT 2012

medium

0.001

0.01

1

0.05

Q75. A galvanometer of resistance, G, is shunted by a resistance S ohm. To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is Source: orcusprep.in

AIPMT 2011

hard

$\frac{G^2}{(S + G)}$

$\frac{G}{(S + G)}$

$\frac{S^2}{(S + G)}$

$\frac{SG}{(S + G)}$

Q76. A galvanometer has a coil of resistance 100 ohm and gives a full scale deflection for 30 mA current. If it is work as a voltmeter of 30 volt range, the resistance required to be added will be Source: orcusprep.in

AIPMT 2010

easy

900 Ω

1800 Ω

500 Ω

1000 Ω

Q77. A galvanometer having a coil of resistance 60 Ω shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by Source: orcusprep.in

AIPMT 2009

medium

putting in parallel a resistance of 15 Ω

putting in series a resistance of 15 Ω

putting in series a resistance of 240 Ω

putting in parallel a resistance of 240 Ω

Q78. A galvanometer of resistance 50 Ω is connected to a battery of 3 V along with a resistance of 2950 Ω in series. A full scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions, the resistance in series should be Source: orcusprep.in

AIPMT 2008

hard

4450 Ω

6050 Ω

5050 Ω

5550 Ω

Q79. The resistance of an ammeter is 13 Ω and its scale is graduated for a current upto 100 amps. After an additional shunt has been connected to this ammeter it becomes possible to measure currents upto 750 amperes by this meter. The value of shunt resistance is Source: orcusprep.in

AIPMT 2007

medium

2 Ω

0.2 Ω

2 kΩ

20 Ω

Q80. A galvanometer of 50 ohm resistance has 25 divisions. A current of 4 × 10⁻⁴ ampere gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of 25 volts, it should be connected with a resistance of Source: orcusprep.in

AIPMT 2004

medium

2450 Ω in series

2500 Ω as a shunt

2450 Ω as a shunt

2550 Ω in series

Q81. To convert a galvanometer into a voltmeter one should connect a Source: orcusprep.in

AIPMT 2004

easy

high resistance in series with galvanometer

low resistance in series with galvanometer

high resistance in parallel with galvanometer

low resistance in parallel with galvanometer

Q82. A galvanometer having a resistance of 9 ohm is shunted by a wire of resistance 2 ohm. If the total current is 1 amp, the part of it passing through the shunt will be Source: orcusprep.in

AIPMT 1998

medium

0.8 amp

0.2 amp

0.25 amp

0.5 amp

Q83. To convert a galvanometer into a ammeter, one needs to connect a Source: orcusprep.in

AIPMT 1992

easy

low resistance in parallel

high resistance in parallel

low resistance in series

high resistance in series

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Physics - Moving Charges and Magnetism-PYQ

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Physics - Moving Charges and Magnetism-PYQ

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