Magnetic Effects of Current and Magnetism — DPP 2

20 NEET questions from Magnetic Effects of Current and Magnetism, with answers and explanations. Attempt it as a timed test to get scoring, accuracy breakdown and mistake tracking.

Attempt this test free 20 questions · 30 minutes · +80 marks
1
Magnetic field at point O will be :-
Magnetic Effects of Current and Magnetism – NEET-9252
  1. A $\frac { \mu _ { 0 } \mathrm { I } } { 2 \mathrm { R } } \otimes$
  2. B $\frac { \mu _ { 0 } \mathrm { I } } { 2 \mathrm { R } } \odot$
  3. C $\frac { \mu _ { 0 } \mathrm { I } } { 2 \mathrm { R } } \left( 1 - \frac { 1 } { \pi } \right) \otimes$
  4. D $\frac { \mu _ { 0 } \mathrm { I } } { 2 \mathrm { R } } \left( 1 + \frac { 1 } { \pi } \right) \odot$
Show answer

Correct answer: C

2
An α-particle experiences a force of $3.84 \times 10 ^ { - 14 } \mathrm {~N}$ when it moves perpendicular to magnetic field of 0.2 Wb/m$^{2}$ then speed of the α-particle is :-
  1. A $6.0 \times 10 ^ { 5 } \mathrm {~m} / \mathrm { sec }$
  2. B $5.0 \times 10 ^ { 5 } \mathrm {~m} / \mathrm { sec }$
  3. C $1.2 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { sec }$
  4. D $3.8 \times 10 ^ { 6 } \mathrm {~m} / \mathrm { sec }$
Show answer

Correct answer: A

3
If an electron enters a magnetic field with its velocity pointing in the same direction as the magnetic field then :-
  1. A the electron will turn towards right
  2. B the electron will turn towards left
  3. C the velocity of the electron will increase
  4. D the velocity of the electron will remain unchanged
Show answer

Correct answer: D

4
Cathode rays are moving between the poles of a magnet. Due to the effect of magnetic field of magnet :-
Magnetic Effects of Current and Magnetism – NEET-9352
  1. A velocity of rays increases
  2. B velocity of rays decreases
  3. C rays deflected towards south pole
  4. D rays deflected in upward direction and perpendicular to the plane of the paper
Show answer

Correct answer: D

5
Mean radius of a toroid is 10 cm and number of turns are 500. If current flowing through it is 0.1 ampere then value of magnetic field (in tesla) for toroid :-
  1. A $10 ^ { - 2 }$
  2. B $10 ^ { - 5 }$
  3. C $10 ^ { - 3 }$
  4. D $10 ^ { - 4 }$
Show answer & explanation

Correct answer: D

$\mathrm{B}=\mu_{0} \frac{\mathrm{~N}}{2 \pi \mathrm{R}_{\mathrm{m}}} \cdot \mathrm{I} \quad$ (given $\mathrm{R}_{\mathrm{m}}=10 \mathrm{~cm}$)
6
Two particles x and y have equal charges and possessing equal kinetic energy enter in a uniform magnetic field and describe circular path of radius of curvature $r _ { 1 }$ and $r _ { 2 }$ respectively. The ratio of their masses is :-
  1. A $\left( \frac { r _ { 1 } } { r _ { 2 } } \right)$
  2. B $\left( \frac { r _ { 1 } } { r _ { 2 } } \right) ^ { 1 / 2 }$
  3. C $\left( \frac { r _ { 1 } } { r _ { 2 } } \right) ^ { 2 }$
  4. D $\left( \frac { r _ { 2 } } { r _ { 1 } } \right)$
Show answer & explanation

Correct answer: C

Magnetic Effects of Current and Magnetism – NEET-9361
7
When α and β rays are subjected to a magnetic field which is perpendicular to the direction of their motion, with their same speed. The curvature of path of both the particles are :-
  1. A equal
  2. B more for α particles
  3. C more for β particles
  4. D none
Show answer & explanation

Correct answer: C

Magnetic Effects of Current and Magnetism – NEET-9355
8
In a mass spectrograph an ion A of mass number 24 and charge +e and an ion B of mass number 22 and charge +2e are entered in transverse magnetic field with same velocity. The ratio of radii of their paths respectively :-
  1. A $\frac { 11 } { 24 }$
  2. B $\frac { 12 } { 11 }$
  3. C $\frac { 11 } { 22 }$
  4. D $\frac { 24 } { 11 }$
Show answer & explanation

Correct answer: D

Magnetic Effects of Current and Magnetism – NEET-9363
9
If length and number of turns becomes half for a solenoid then value of magnetic field becomes:-
  1. A twice
  2. B same
  3. C half
  4. D one fourth
Show answer & explanation

Correct answer: B

Magnetic Effects of Current and Magnetism – NEET-9339
10
Which of the following particle will experiences maximum magnetic force, when projected with the same velocity perpendicular to a magnetic field :-
  1. A electron
  2. B proton
  3. C He$^{+}$
  4. D Li$^{++}$
Show answer & explanation

Correct answer: D

F = qvB
⇒ F ∝ q (v, B → same)
11
A charge having q/m equal to $10 ^ { 8 } \mathrm { C } / \mathrm { kg }$ and with velocity $3 \times 10 ^ { 5 } \mathrm {~m} / \mathrm { s }$ enters into a uniform magnetic field B = 0.3 T at an angle $30 ^ { \circ }$ with direction of field. Then radius will be :-
  1. A 0.01 cm
  2. B 0.5 cm
  3. C 1 cm
  4. D 2 cm
Show answer & explanation

Correct answer: B

$\begin{aligned} r & =\frac{m v \sin \theta}{q B}=\frac{v \sin \theta}{(q / m) B} \\ & =\frac{1}{10^{8}} \times \frac{3 \times 10^{5}}{0.3} \times \frac{1}{2}=5 \times 10^{-3} \mathrm{~m}=0.5 \mathrm{~cm}\end{aligned}$
12
Following charge has maximum frequency of rotation in uniform transverse magnetic field :-
  1. A a proton
  2. B an alpha particle
  3. C an electron
  4. D a neutron
Show answer & explanation

Correct answer: C

$f=\frac{q B}{2 \pi m} \Rightarrow f \propto \frac{q}{m}$
13
A proton, deutron and an α-particle are accelerated by same potential, enter in uniform magnetic field perpendicularly. Ratio of radii of circular path respectively :-
  1. A $1 : \sqrt { 2 } : \sqrt { 2 }$
  2. B 2 : 2 : 1
  3. C 1 : 2 : 1
  4. D 1 : 1 : 1
Show answer & explanation

Correct answer: A

$\begin{array}{l}\mathrm{r}_{\mathrm{p}}: \mathrm{r}_{\mathrm{d}}: \mathrm{r}_{\alpha} \\ \mathrm{r} \propto \sqrt{\frac{\mathrm{m}}{\mathrm{q}}} \\ \sqrt{\frac{1}{1}}: \sqrt{\frac{2}{1}}: \sqrt{\frac{4}{2}}=1: \sqrt{2}: \sqrt{2}\end{array}$
14
A proton and an alpha particle are separately projected in a region where a uniform magnetic field exists. The initial velocities are perpendicular to the direction of magnetic field. If both the particles move along circles of equal radii, the ratio of momentum of proton to alpha particle $\left( \frac { \mathrm { P } _ { \mathrm { p } } } { \mathrm { P } _ { \alpha } } \right)$ is :-
  1. A 1
  2. B $\frac{1}{2}$
  3. C 2
  4. D $\frac{1}{4}$
Show answer & explanation

Correct answer: B

Magnetic Effects of Current and Magnetism – NEET-9351
15
Two identically charged particles A and B initially at rest, are accelerated by a common potential difference V. They enters into a uniform transverse magnetic field B and describe a circular path of radii $r _ { 1 }$ and $r _ { 2 }$ respectively then their mass ratio is :-
  1. A $\left( \frac { r _ { 1 } } { r _ { 2 } } \right) ^ { 2 }$
  2. B $\left( \frac { r _ { 2 } } { r _ { 1 } } \right) ^ { 2 }$
  3. C $\left( \frac { r _ { 1 } } { r _ { 2 } } \right)$
  4. D $\left( \frac { r _ { 2 } } { r _ { 1 } } \right)$
Show answer & explanation

Correct answer: A

Magnetic Effects of Current and Magnetism – NEET-9356
16
A charge particle is moving in the direction of a magnetic field. The magnetic force acting on the particle :-
  1. A is in the direction of its velocity
  2. B is in the direction opposite to its velocity
  3. C is perpendicular to its velocity
  4. D is zero
Show answer

Correct answer: D

17
If number of turns and current become double for any solenoid, then value of magnetic field becomes :-
  1. A twice
  2. B same
  3. C half
  4. D four times
Show answer & explanation

Correct answer: D

$\begin{aligned} B & =\mu_{0} \frac{N}{\ell} I \\ B^{\prime} & =\frac{\mu_{0}(2 N)(2 I)}{\ell}=4 B\end{aligned}$
18
A long solenoid having 200 turns/cm and carries current i. Magnetic field at its axis is $6.28 \times 10 ^ { - 2 } \mathrm { wb } / \mathrm { m } ^ { 2 }$. An another solenoid having 100 turns/cm and carries $\frac { \mathrm { i } } { 3 }$ current, then magnetic field at its axis will be :-
  1. A $1.05 \times 10 ^ { - 4 } \mathrm {~Wb} / \mathrm { m } ^ { 2 }$
  2. B $1.05 \times 10 ^ { - 2 } \mathrm {~Wb} / \mathrm { m } ^ { 2 }$
  3. C $1.05 \times 10 ^ { - 5 } \mathrm {~Wb} / \mathrm { m } ^ { 2 }$
  4. D $1.05 \times 10 ^ { - 3 } \mathrm {~Wb} / \mathrm { m } ^ { 2 }$
Show answer & explanation

Correct answer: B

Magnetic Effects of Current and Magnetism – NEET-9350
19
An electron of kinetic energy of $7.2 \times 10 ^ { - 18 } \mathrm {~J}$ is revolving in a circular path in magnetic field $9 \times 10 ^ { - 5 } \mathrm {~Wb} / \mathrm { m } ^ { 2 }$ then radius of its circular path is:-
  1. A 1.25 cm
  2. B 2.5 m
  3. C 2.5 cm
  4. D 25.0 cm
Show answer

Correct answer: D

20
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 :-
  1. A B/2
  2. B B
  3. C 2B
  4. D 4B
Show answer & explanation

Correct answer: B

Magnetic Effects of Current and Magnetism – NEET-9349

Attempt this as a timed test

Reading answers is not the same as sitting the paper. Attempt it timed and you get your score, per-question timing, and the mistakes tracked for revision.

Start free

More Magnetic Effects of Current and Magnetism tests

Magnetic Effects of Current and Magnetism — DPP 1 20 Q Magnetic Effects of Current and Magnetism — DPP 3 20 Q
All Magnetic Effects of Current and Magnetism tests →