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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 6801. |
Two galvanometers A and B require 3mA and 5mA respectively to produce the same deflection of 10 divisions. Then [Kerala PET 2001] |
| A. | A is more sensitive than B |
| B. | B is more sensitive than A |
| C. | A and B are equally sensitive |
| D. | Sensitiveness of B is 5/3 times that of A |
| Answer» B. B is more sensitive than A | |
| 6802. |
A straight conductor carries a current of 5A. An electron travelling with a speed of \[5\times {{10}^{6}}m{{s}^{-1}}\]parallel to the wire at a distance of 0.1m from the conductor, experiences a force of [Kerala PET 2001] |
| A. | \[8\times {{10}^{-20}}N\] |
| B. | \[3.2\times {{10}^{-19}}N\] |
| C. | \[8\times {{10}^{-18}}N\] |
| D. | \[1.6\times {{10}^{-19}}N\] |
| Answer» D. \[1.6\times {{10}^{-19}}N\] | |
| 6803. |
A small cylindrical soft iron piece is kept in a galvanometer so that [MP PMT 2001] |
| A. | A radial uniform magnetic field is produced |
| B. | A uniform magnetic field is produced |
| C. | There is a steady deflection of the coil |
| D. | All of these |
| Answer» E. | |
| 6804. |
A, B and C are parallel conductors of equal length carrying currents I, I and 2I respectively. Distance between A and B is x. Distance between B and C is also x. \[{{F}_{1}}\] is the force exerted by B on A and F2 is the force exerted by B on A choose the correct answer [Kerala PET 2001] |
| A. | \[{{F}_{1}}=2{{F}_{2}}\] |
| B. | \[{{F}_{2}}=2{{F}_{1}}\] |
| C. | \[{{F}_{1}}={{F}_{2}}\] |
| D. | \[{{F}_{1}}=-{{F}_{2}}\] |
| Answer» E. | |
| 6805. |
A circular coil having N turns is made from a wire of length L meter. If a current I ampere is passed through it and is placed in a magnetic field of B Tesla, the maximum torque on it is [MP PMT 2001] |
| A. | Directly proportional to N |
| B. | Inversely proportional to N |
| C. | Inversely proportional to \[{{N}^{2}}\] |
| D. | Independent of N |
| Answer» B. Inversely proportional to N | |
| 6806. |
An arbitrary shaped closed coil is made of a wire of length L and a current I ampere is flowing in it. If the plane of the coil is perpendicular to magnetic field \[\overset{\to }{\mathop{B}}\,\], the force on the coil is [MP PMT 2001] |
| A. | Zero |
| B. | IBL |
| C. | 2IBL |
| D. | \[\frac{1}{2}IBL\] |
| Answer» B. IBL | |
| 6807. |
A current i flows in a circular coil of radius r. If the coil is placed in a uniform magnetic field B with its plane parallel to the field, magnitude of the torque that acts on the coil is [MP PET 2001] |
| A. | Zero |
| B. | \[2\pi \,r\,i\,B\] |
| C. | \[\pi \,{{r}^{2}}\,i\,B\] |
| D. | \[2\pi \,{{r}^{2}}\,i\,B\] |
| Answer» D. \[2\pi \,{{r}^{2}}\,i\,B\] | |
| 6808. |
If a wire of length 1 meter placed in uniform magnetic field 1.5 Tesla at angle \[{{30}^{o}}\] with magnetic field. The current in a wire 10 amp. Then force on a wire will be [RPET 2001] |
| A. | 7.5 N |
| B. | 1.5 N |
| C. | 0.5 N |
| D. | 2.5 N |
| Answer» B. 1.5 N | |
| 6809. |
If two streams of protons move parallel to each other in the same direction, then they [MP PET 1999; AIIMS 2004] |
| A. | Do not exert any force on each other |
| B. | Repel each other |
| C. | Attract each other |
| D. | Get rotated to be perpendicular to each other |
| Answer» C. Attract each other | |
| 6810. |
What is shape of magnet in moving coil galvanometer to make the radial magnetic field [RPET 2001] |
| A. | Concave |
| B. | Horse shoe magnet |
| C. | Convex |
| D. | None of these |
| Answer» B. Horse shoe magnet | |
| 6811. |
The relation between voltage sensitivity (\[{{\sigma }_{V}}\]) and current sensitivity \[({{\sigma }_{i}})\] of a moving coil galvanometer is (Resistance of Galvanometer = G) [CPMT 2001] |
| A. | \[\frac{{{\sigma }_{i}}}{G}={{\sigma }_{V}}\] |
| B. | \[\frac{{{\sigma }_{_{V}}}}{G}={{\sigma }_{i}}\] |
| C. | \[\frac{G}{{{\sigma }_{V}}}={{\sigma }_{i}}\] |
| D. | \[\frac{G}{{{\sigma }_{i}}}={{\sigma }_{V}}\] |
| Answer» B. \[\frac{{{\sigma }_{_{V}}}}{G}={{\sigma }_{i}}\] | |
| 6812. |
A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to electron stream and above it. If the current in the conductor is from left to right then what will be the effect on electron stream [Roorkee 2000] |
| A. | The electron stream will be pulled upward |
| B. | The electron stream will be pulled downward |
| C. | The electron stream will be retarted |
| D. | The electron beam will be speeded up towards the right |
| Answer» C. The electron stream will be retarted | |
| 6813. |
A long wire A carries a current of 10 amp. Another long wire B, Which is parallel to A and separated by 0.1m from A, carries a current of 5 amp, in the opposite direction to that in A. what is the magnitude and nature of the force experienced per unit length of B \[({{\mu }_{0}}=4\pi \times {{10}^{-7}}\,weber/amp\text{-}m)\] [MP PET 2000] |
| A. | Repulsive force of \[{{10}^{-4}}N/m\] |
| B. | Attractive force of \[{{10}^{-4}}N/m\] |
| C. | Repulsive force of \[2\pi \times {{10}^{-5}}N/m\] |
| D. | Attractive force of \[2\pi \times {{10}^{-5}}N/m\] |
| Answer» B. Attractive force of \[{{10}^{-4}}N/m\] | |
| 6814. |
The magnetic moment of a circular coil carrying current is [MP PET 2000] |
| A. | Directly proportional to the length of the wire in the coil |
| B. | Inversely proportional to the length of the wire in the coil |
| C. | Directly proportional to the square of the length of the wire in the coil |
| D. | Inversely proportional to the square of the length of the wire in the coil |
| Answer» D. Inversely proportional to the square of the length of the wire in the coil | |
| 6815. |
Due to the flow of current in a circular loop of radius R, the magnetic induction produced at the centre of the loop is B. The magnetic moment of the loop is \[({{\mu }_{0}}=\text{permeability}\,\text{constant)}\] [MP PET 2000] |
| A. | \[B{{R}^{3}}/2\pi {{\mu }_{0}}\] |
| B. | \[2\pi B{{R}^{3}}/{{\mu }_{0}}\] |
| C. | \[B{{R}^{2}}/2\pi {{\mu }_{0}}\] |
| D. | \[2\pi B{{R}^{2}}/{{\mu }_{0}}\] |
| Answer» C. \[B{{R}^{2}}/2\pi {{\mu }_{0}}\] | |
| 6816. |
A circular loop has a radius of 5 cm and it is carrying a current of 0.1 amp. Its magnetic moment is [MP PMT 2000] |
| A. | \[1.32\times {{10}^{-4}}amp-{{m}^{2}}\] |
| B. | \[2.62\times {{10}^{-4}}amp\text{-}{{m}^{2}}\] |
| C. | \[5.25\times {{10}^{-4}}amp\text{-}{{m}^{2}}\] |
| D. | \[7.85\times {{10}^{-4}}amp\text{-}{{m}^{2}}\] |
| Answer» E. | |
| 6817. |
What is the net force on the square coil [DCE 2000; RPMT 2000] |
| A. | \[25\times {{10}^{-7}}N\] moving towards wire |
| B. | \[25\times {{10}^{-7}}N\] moving away from wire |
| C. | \[35\times {{10}^{-7}}N\] moving towards wire |
| D. | \[35\times {{10}^{-7}}N\] moving away from wire |
| Answer» B. \[25\times {{10}^{-7}}N\] moving away from wire | |
| 6818. |
Through two parallel wires A and B, 10 and 2 ampere of currents are passed respectively in opposite direction. If the wire A is infinitely long and the length of the wire B is 2 m, the force on the conductor B, which is situated at 10 cm distance from A will be [CPMT 1988; MP PMT 1994] |
| A. | \[8\times {{10}^{-5}}N\] |
| B. | \[4\times {{10}^{-7}}N\] |
| C. | \[4\times {{10}^{-5}}N\] |
| D. | \[4\pi \times {{10}^{-7}}N\] |
| Answer» B. \[4\times {{10}^{-7}}N\] | |
| 6819. |
If m is magnetic moment and B is the magnetic field, then the torque is given by [DCE 2000] |
| A. | \[\overset{\to \,\,\to }{\mathop{m.B}}\,\] |
| B. | \[\frac{\overset{\to }{\mathop{|m|}}\,}{\overset{\to }{\mathop{|B|}}\,}\] |
| C. | \[\overset{\to \,\,\,\,\to }{\mathop{m\times B}}\,\] |
| D. | \[\overset{\to \,\,\,\,\,\,\,\,\,\,\to }{\mathop{|m|.\,|B|}}\,\] |
| Answer» D. \[\overset{\to \,\,\,\,\,\,\,\,\,\,\to }{\mathop{|m|.\,|B|}}\,\] | |
| 6820. |
A circular loop of area \[0.01{{m}^{2}}\] carrying a current of 10 A, is held perpendicular to a magnetic field of intensity 0.1T. The torque acting on the loop is [Pb. PMT 2000] |
| A. | Zero |
| B. | 0.01 N-m |
| C. | 0.001 N-m |
| D. | 0.8 N-m |
| Answer» B. 0.01 N-m | |
| 6821. |
Two parallel beams of electrons moving in the same direction produce a mutual force [MP PET 1996; DCE 1999] |
| A. | Of attraction in plane of paper |
| B. | Of repulsion in plane of paper |
| C. | Upwards perpendicular to plane of paper |
| D. | Downwards perpendicular to plane of paper |
| Answer» C. Upwards perpendicular to plane of paper | |
| 6822. |
Two long parallel wires carrying equal current separated by 1m, exert a force of \[2\times {{10}^{-7}}N/m\] on one another. The current flowing through them is [AMU (Engg.) 1999] |
| A. | 2.0 A |
| B. | \[2.0\times {{10}^{-7}}A\] |
| C. | 1.0 A |
| D. | \[1.0\times {{10}^{-7}}A\] |
| Answer» D. \[1.0\times {{10}^{-7}}A\] | |
| 6823. |
A circular coil of diameter 7cm has 24 turns of wire carrying current of 0.75A. The magnetic moment of the coil is [AMU (Med.) 1999] |
| A. | \[6.9\times {{10}^{-2}}amp-{{m}^{2}}\] |
| B. | \[2.3\times {{10}^{-2}}amp\text{-}\,{{m}^{2}}\] |
| C. | \[{{10}^{-2}}amp-{{m}^{2}}\] |
| D. | \[{{10}^{-3}}amp-{{m}^{2}}\] |
| Answer» B. \[2.3\times {{10}^{-2}}amp\text{-}\,{{m}^{2}}\] | |
| 6824. |
The current sensitivity of a moving coil galvanometer can be increased by [Roorkee 1999] |
| A. | Increasing the magnetic field of the permanent magnet |
| B. | Increasing the area of the deflecting coil |
| C. | Increasing the number of turns in the coil |
| D. | Increasing the restoring couple of the coil |
| Answer» C. Increasing the number of turns in the coil | |
| 6825. |
Two parallel wires in free space are 10 cm apart and each carries a current of 10 A in the same direction. The force one wire exerts on the other per metre of length is [CBSE PMT 1997; AFMC 1999] |
| A. | \[2\times {{10}^{-4}}N\], attractive |
| B. | \[2\times {{10}^{-4}}N\], repulsive |
| C. | \[2\times {{10}^{-7}}N\], attractive |
| D. | \[2\times {{10}^{-7}}N\], repulsive |
| Answer» B. \[2\times {{10}^{-4}}N\], repulsive | |
| 6826. |
A straight wire of length 0.5 metre and carrying a current of 1.2 ampere placed in a uniform magnetic field of induction 2 Tesla. The magnetic field is perpendicular to the length of the wire. The force on the wire is [CBSE PMT 1992; BHU 1998; DPMT 2001; RPET 2003] |
| A. | 2.4 N |
| B. | 1.2 N |
| C. | 3.0 N |
| D. | 2.0 N |
| Answer» C. 3.0 N | |
| 6827. |
A power line lies along the east-west direction and carries a current of 10 ampere. The force per metre due to the earth's magnetic field of \[{{10}^{-4}}\,tesla\] is [Roorkee 1992] |
| A. | \[{{10}^{-5}}N\] |
| B. | \[{{10}^{-4}}N\] |
| C. | \[{{10}^{-3}}N\] |
| D. | \[{{10}^{-2}}N\] |
| Answer» D. \[{{10}^{-2}}N\] | |
| 6828. |
A circular loop carrying a current is replaced by an equivalent magnetic dipole. A point on the axis of the loop is [MNR 1998] |
| A. | An end-on position |
| B. | A broad side-on position |
| C. | Both (a) and (b) |
| D. | Neither (a) nor (b) |
| Answer» B. A broad side-on position | |
| 6829. |
A coil carrying electric current is placed in uniform magnetic field, then [CBSE PMT 1993] |
| A. | Torque is formed |
| B. | E.M.f. is induced |
| C. | Both (a) and (b) are correct |
| D. | None of these |
| Answer» B. E.M.f. is induced | |
| 6830. |
A vertical wire carrying a current in the upward direction is placed in horizontal magnetic field directed towards north. The wire will experience a force directed towards [SCRA 1994] |
| A. | North |
| B. | South |
| C. | East |
| D. | West |
| Answer» E. | |
| 6831. |
Three long, straight and parallel wires carrying currents are arranged as shown in the figure. The wire C which carries a current of 5.0 amp is so placed that it experiences no force. The distance of wire C from wire D is then [AMU 1995] |
| A. | 9 cm |
| B. | 7 cm |
| C. | 5 cm |
| D. | 3 cm |
| Answer» B. 7 cm | |
| 6832. |
A triangular loop of side l carries a current I. It is placed in a magnetic field B such that the plane of the loop is in the direction of B. The torque on the loop is [MP PET 2003] |
| A. | Zero |
| B. | IBl |
| C. | \[\frac{\sqrt{3}}{2}I{{l}^{2}}{{B}^{2}}\] |
| D. | \[\frac{\sqrt{3}}{4}IB{{l}^{2}}\] |
| Answer» E. | |
| 6833. |
In hydrogen atom, the electron is making \[6.6\times {{10}^{15}}\,rev/\sec \] around the nucleus in an orbit of radius 0.528 Å. The magnetic moment \[(A-{{m}^{2}})\] will be [MP PET 1999] |
| A. | \[1\times {{10}^{-15}}\] |
| B. | \[1\times {{10}^{-10}}\] |
| C. | \[1\times {{10}^{-23}}\] |
| D. | \[1\times {{10}^{-27}}\] |
| Answer» D. \[1\times {{10}^{-27}}\] | |
| 6834. |
A current carrying small loop behaves like a small magnet. If A be its area and M its magnetic moment, the current in the loop will be [MP PMT/PET 1998; RPET 2001; MP PMT 2003] |
| A. | \[M/A\] |
| B. | \[A/M\] |
| C. | MA |
| D. | \[{{A}^{2}}M\] |
| Answer» B. \[A/M\] | |
| 6835. |
If a current is passed in a spring, it [MP PMT/PET 1998; AIEEE 2002] |
| A. | Gets compressed |
| B. | Gets expanded |
| C. | Oscillates |
| D. | Remains unchanged |
| Answer» B. Gets expanded | |
| 6836. |
A rectangular coil \[20\,cm\times 20\,cm\] has 100 turns and carries a current of 1 A. It is placed in a uniform magnetic field B =0.5 T with the direction of magnetic field parallel to the plane of the coil. The magnitude of the torque required to hold this coil in this position is [MP PMT 1997] |
| A. | Zero |
| B. | 200 N-m |
| C. | 2 N-m |
| D. | 10 N-m |
| Answer» D. 10 N-m | |
| 6837. |
The coil of a galvanometer consists of 100 turns and effective area of 1 square cm. The restoring couple is \[{{10}^{-8}}\,N-m/radian\]. The magnetic field between the pole pieces is 5 T. The current sensitivity of this galvanometer will be [MP PMT 1997] |
| A. | \[5\times {{10}^{4}}\,rad/\mu \,amp\] |
| B. | \[5\times {{10}^{-6}}\,per\,amp\] |
| C. | \[2\times {{10}^{-7}}\,per\,amp\] |
| D. | \[5\,rad/\mu \,amp\] |
| Answer» E. | |
| 6838. |
A conducting circular loop of radius r carries a constant current i. It is placed in a uniform magnetic field \[\overrightarrow{B}\], such that \[\overrightarrow{B}\] is perpendicular to the plane of the loop. The magnetic force acting on the loop is [BIT 1992; MP PET 1994; IIT 1983; MP PMT 1999; AMU (Engg.) 2000] |
| A. | \[ir\overrightarrow{B}\] |
| B. | \[2\pi ri\overrightarrow{B}\] |
| C. | Zero |
| D. | \[\pi ri\overrightarrow{B}\] |
| Answer» D. \[\pi ri\overrightarrow{B}\] | |
| 6839. |
A conductor in the form of a right angle ABC with AB = 3 cm and BC = 4 cm carries a current of 10 A. There is a uniform magnetic field of 5 T perpendicular to the plane of the conductor. The force on the conductor will be [MP PMT 1997] |
| A. | 1.5 N |
| B. | 2.0 N |
| C. | 2.5 N |
| D. | 3.5 N |
| Answer» D. 3.5 N | |
| 6840. |
A current of 5 ampere is flowing in a wire of length 1.5 metres. A force of 7.5 N acts on it when it is placed in a uniform magnetic field of 2 Tesla. The angle between the magnetic field and the direction of the current is [MP PET 1997; Pb. PET 2003] |
| A. | \[30{}^\circ \] |
| B. | 45° |
| C. | 60° |
| D. | 90° |
| Answer» B. 45° | |
| 6841. |
A 100 turns coil shown in figure carries a current of 2 amp in a magnetic field \[B=0.2\,Wb/{{m}^{2}}\]. The torque acting on the coil is [MP PET 1997] |
| A. | 0.32 Nm tending to rotate the side AD out of the page |
| B. | 0.32 Nm tending to rotate the side AD into the page |
| C. | 0.0032 Nm tending to rotate the side AD out of the page |
| D. | 0.0032 Nm tending to rotate the side AD into the page |
| Answer» B. 0.32 Nm tending to rotate the side AD into the page | |
| 6842. |
Three long, straight and parallel wires carrying currents are arranged as shown in figure. The force experienced by 10 cm length of wire Q is [MP PET 1997] |
| A. | \[1.4\times {{10}^{-4}}N\] towards the right |
| B. | \[1.4\times {{10}^{-4}}N\] towards the left |
| C. | \[2.6\times {{10}^{-4}}N\] to the right |
| D. | \[2.6\times {{10}^{-4}}N\] to the left |
| Answer» B. \[1.4\times {{10}^{-4}}N\] towards the left | |
| 6843. |
Two parallel conductors A and B of equal lengths carry currents I and 10 I, respectively, in the same direction. Then [MP PET 2003] |
| A. | A and B will repel each other with same force |
| B. | A and B will attract each other with same force |
| C. | A will attract B, but B will repel A |
| D. | A and B will attract each other with different forces |
| Answer» C. A will attract B, but B will repel A | |
| 6844. |
A metallic loop is placed in a magnetic field. If a current is passed through it, then [UPSEAT 2003] |
| A. | The ring will feel a force of attraction |
| B. | The ring will feel a force of repulsion |
| C. | It will move to and fro about its centre of gravity |
| D. | None of these |
| Answer» E. | |
| 6845. |
The sensitiveness of a moving coil galvanometer can be increased by decreasing [MP PMT 1996] |
| A. | The number of turns in the coil |
| B. | The area of the coil |
| C. | The magnetic field |
| D. | The couple per unit twist of the suspension |
| Answer» E. | |
| 6846. |
The pole pieces of the magnet used in a pivoted coil galvanometer are [MP PET 1996] |
| A. | Plane surfaces of a bar magnet |
| B. | Plane surfaces of a horse-shoe magnet |
| C. | Cylindrical surfaces of a bar magnet |
| D. | Cylindrical surfaces of a horse-shoe magnet |
| Answer» E. | |
| 6847. |
The expression for the torque acting on a coil having area of cross-section A, number of turns n, placed in a magnetic field of strength B, making an angle \[\theta \] with the normal to the plane of the coil, when a current i is flowing in it, will be [MP PET 1996] |
| A. | \[ni\,AB\tan \theta \] |
| B. | \[ni\,AB\cos \theta \] |
| C. | \[ni\,AB\sin \theta \] |
| D. | \[ni\,AB\] |
| Answer» D. \[ni\,AB\] | |
| 6848. |
A current carrying loop is free to turn in a uniform magnetic field. The loop will then come into equilibrium when its plane is inclined at [CBSE PMT 1992; Haryana CEE 1996] |
| A. | \[0{}^\circ \] to the direction of the field |
| B. | \[45{}^\circ \] to the direction of the field |
| C. | \[90{}^\circ \] to the direction of the field |
| D. | \[135{}^\circ \] to the direction of the field |
| Answer» D. \[135{}^\circ \] to the direction of the field | |
| 6849. |
A circular coil of radius 4 cm and of 20 turns carries a current of 3 amperes. It is placed in a magnetic field of intensity of 0.5\[weber/{{m}^{2}}\]. The magnetic dipole moment of the coil is [MP PMT 2001] |
| A. | 0.15 \[ampere-{{m}^{2}}\] |
| B. | 0.3 \[ampere-{{m}^{2}}\] |
| C. | 0.45 \[ampere-{{m}^{2}}\] |
| D. | 0.6 \[ampere-{{m}^{2}}\] |
| Answer» C. 0.45 \[ampere-{{m}^{2}}\] | |
| 6850. |
A current carrying rectangular coil is placed in a uniform magnetic field. In which orientation, the coil will not tend to rotate [MP PMT 1995] |
| A. | The magnetic field is parallel to the plane of the coil |
| B. | The magnetic field is perpendicular to the plane of the coil |
| C. | The magnetic field is at 45o with the plane of the coil |
| D. | Always in any orientation |
| Answer» C. The magnetic field is at 45o with the plane of the coil | |