Magnetic Effects of Current and Magnetism — DPP 1

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
Radius of a current carrying coil is 'R'. The ratio of magnetic field at a axial point which is R distance away from the centre of the coil to the magnetic field at the centre of the coil:-
  1. A $\left( \frac { 1 } { 2 } \right) ^ { 1 / 2 }$
  2. B $\frac { 1 } { 2 }$
  3. C $\left( \frac { 1 } { 2 } \right) ^ { 3 / 2 }$
  4. D $\frac { 1 } { 4 }$
Show answer & explanation

Correct answer: C

Magnetic Effects of Current and Magnetism – NEET-9260
2
Figure shows a square shape loop, whose one arm BC produces magnetic field B at the centre of coil. The resultant magnetic field due to all the arms will be :-
Magnetic Effects of Current and Magnetism – NEET-9247
  1. A 4B
  2. B B/2
  3. C B
  4. D 2B
Show answer & explanation

Correct answer: A

$\begin{aligned} \mathrm{B}_{\text {net }} & =\mathrm{B}_{1}+\mathrm{B}_{2}+\mathrm{B}_{3}+\mathrm{B}_{4} \\ & =4 \mathrm{~B} \quad\left(\mathrm{~B}_{1}=\mathrm{B}_{2}=\mathrm{B}_{3}=\mathrm{B}_{4}=\mathrm{B}\right)\end{aligned}$
3
The wire in the figure carries a current i and consists of a circular arc of radius R and central angle $\frac { \pi } { 2 } \mathrm { rad }$, and two straight sections whose extensions intersect the centre C of the arc. The magnetic field $\overrightarrow { \mathrm { B } }$ that the current produces at C is :-
Magnetic Effects of Current and Magnetism – NEET-9336
  1. A $| \vec { B } | = \frac { \mu _ { 0 } i } { 8 R }$ into the plane of the figure
  2. B $| \vec { B } | = \frac { \mu _ { 0 } i } { 8 R }$ out of the plane of the figure
  3. C $| \overrightarrow { \mathrm { B } } | = \frac { \mu _ { 0 } \mathrm { i } } { 8 \pi \mathrm { R } }$ into the plane of the figure
  4. D $| \vec { B } | = \frac { \mu _ { 0 } i } { 8 \pi R }$ out of the plane of the figure
Show answer & explanation

Correct answer: A

Magnetic Effects of Current and Magnetism – NEET-9336
4
A coil of one loop is made by a wire of length L and there after a coil of two loops is made by same wire. The ratio of magnetic field at the centre of coils respectively :-
  1. A 1 : 4
  2. B 1 : 1
  3. C 1 : 8
  4. D 4 : 1
Show answer & explanation

Correct answer: A

B ∝ N$^{2}$ (for l = constant)
5
Two infinite long parallel wires carry equal currents in same direction. The magnetic field at mid point between the two wires is :-
  1. A Twice the magnetic field produced due to each of the wires
  2. B Half of the magnetic field produced due to each of the wires
  3. C Square of the magnetic field produced due to each of the wires
  4. D Zero
Show answer

Correct answer: D

6
When the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its centre will become :-
  1. A Same
  2. B Four times
  3. C Half
  4. D Double
Show answer

Correct answer: A

7
1A current flows through an infinitely long straight wire. The magnetic field produced at a point 1 m. away from it is :-
  1. A $2 \times 10 ^ { - 3 } \mathrm {~T}$
  2. B $\frac { 2 } { 10 } \mathrm {~T}$
  3. C $2 \times 10 ^ { - 7 } \mathrm {~T}$
  4. D $2 \pi \times 10 ^ { - 6 } \mathrm {~T}$
Show answer

Correct answer: C

8
In the shown figure magnetic field at point A will be :-
Magnetic Effects of Current and Magnetism – NEET-9265
  1. A $\frac { \mu _ { 0 } \mathrm { I } } { 4 \pi }$
  2. B $\frac { \mu _ { 0 } I } { 4 R }$
  3. C $\frac { \mu _ { 0 } I } { 4 \pi R }$
  4. D Zero
Show answer

Correct answer: B

9
Two concentric circular loops of radii 0.08 m and 0.1 m carries current such that magnetic field at the centre is zero. If the current in the outer loop is 8A clockwise, current in the inner loop is :-
  1. A 6.4 A anticlockwise
  2. B 6.4 A clockwise
  3. C 8 A anticlockwise
  4. D 3.2 A clockwise
Show answer & explanation

Correct answer: A

Magnetic Effects of Current and Magnetism – NEET-9264
10
A circular coil of radius R carries an electric current. The magnetic field due the coil at a point on the axis of the coil located at a distance r from the center of the coil, such that r >> R varies as :-
  1. A $1 / r$
  2. B $1 / \mathrm { r } ^ { 3 / 2 }$
  3. C $1 / r ^ { 2 }$
  4. D $1 / r ^ { 3 }$
Show answer & explanation

Correct answer: D

Magnetic Effects of Current and Magnetism – NEET-9263
11
Radius of the current-carrying coil is 'R'. Then ratio of magnetic fields at the centre of the coil to the axial point, which is √3 distance away from the centre of the coil :-
  1. A 1 : 1
  2. B 1 : 2
  3. C 1 : 4
  4. D 8 : 1
Show answer & explanation

Correct answer: D

Magnetic Effects of Current and Magnetism – NEET-9250
12
π ampere current is flowing through a long straight wire. Due to this a field of $5 \times 10 ^ { - 5 } \mathrm {~T}$ produced, then distance of the point from the axis of the wire is :-
  1. A $10 ^ { 4 } \mu _ { 0 } \mathrm {~m}$
  2. B $10 ^ { 5 } \mu _ { 0 } \mathrm {~m}$
  3. C $10 ^ { 6 } \mu _ { 0 } \mathrm {~m}$
  4. D $10 ^ { 8 } \mu _ { 0 } \mathrm {~m}$
Show answer & explanation

Correct answer: A

$B=\frac{\mu_{0} i}{2 \pi d} \Rightarrow d=\frac{\mu_{0} i}{2 \pi B}$
13
A current of 10 A is established in a long wire along positive z-direction. The magnetic field B at the point (1 m, 0, 0) is :-
  1. A $1 \mu \mathrm {~T}$ along the - y direction
  2. B $2 \mu \mathrm {~T}$ along the + y direction
  3. C $1 \mu \mathrm {~T}$ along the $- x$ direction
  4. D $2 \mu \mathrm {~T}$ along the + x direction
Show answer & explanation

Correct answer: B

Magnetic Effects of Current and Magnetism – NEET-9249
14
For the given current distribution the magnetic field at point, 'P' is :-
Magnetic Effects of Current and Magnetism – NEET-9255
  1. A $\frac { \mu _ { 0 } } { 4 \pi } \odot$
  2. B $\frac { \mu _ { 0 } } { \pi } \otimes$
  3. C $\frac { \mu _ { 0 } } { 2 \pi } \otimes$
  4. D $\frac { \mu _ { 0 } } { 2 \pi } \odot$
Show answer & explanation

Correct answer: C

Magnetic Effects of Current and Magnetism – NEET-9255
15
A stationary magnet does not interact with :-
  1. A iron rod
  2. B moving charge
  3. C moving magnet
  4. D stationary charge
Show answer

Correct answer: D

16
A and B are two concentric circular loop carrying current $\mathrm { i } _ { 1 }$ and $\mathrm { i } _ { 2 }$ as shown in figure. If ratio of their radii is 1 : 2 and ratio of the flux densities at the centre O due to A and B is 1 : 3 then the value of $\frac { \mathrm { i } _ { 1 } } { \mathrm { i } _ { 2 } }$ will be :-
Magnetic Effects of Current and Magnetism – NEET-9254
  1. A $\frac { 1 } { 2 }$
  2. B $\frac { 1 } { 3 }$
  3. C $\frac { 1 } { 4 }$
  4. D $\frac { 1 } { 6 }$
Show answer & explanation

Correct answer: D

Magnetic Effects of Current and Magnetism – NEET-9254
17
A horizontal overhead powerline is at a height of 4 m from the ground and carries a current of 100 A from east to west. The magnetic field directly below it on the ground is :-
  1. A $2.5 \times 10 ^ { - 7 } \mathrm {~T}$, southward
  2. B $5 \times 10 ^ { - 6 } \mathrm {~T}$, northward
  3. C $5 \times 10 ^ { - 6 } \mathrm {~T}$, southward
  4. D $2.5 \times 10 ^ { - 7 } \mathrm {~T}$, northward
Show answer

Correct answer: C

18
If radius of coil becomes two times and current becomes half then magnetic field at centre of the coil will be :-
  1. A Two times
  2. B Four times
  3. C Half
  4. D One fourth
Show answer

Correct answer: D

19
A wire is parallel to one arm of a square current carrying loop, which also carries current. Now at any point A within the coil the magnetic field will be :-
Magnetic Effects of Current and Magnetism – NEET-9248
  1. A less than the magnetic field produced due to loop only.
  2. B more than the magnetic field produced due to loop only.
  3. C equal to the earlier.
  4. D zero
Show answer

Correct answer: B

20
The vector form of Biot savart law for a current carrying element is :-
  1. A $\mathrm { d } \overrightarrow { \mathrm { B } } = \frac { \mu _ { 0 } } { 4 \pi } \frac { \mathrm { id } \ell \sin \phi } { \mathrm { r } ^ { 2 } }$
  2. B $\mathrm { d } \overrightarrow { \mathrm { B } } = \frac { \mu _ { 0 } } { 4 \pi } \frac { \mathrm { i } \overrightarrow { \mathrm { d } } \ell \times \hat { \mathrm { r } } } { \mathrm { r } ^ { 2 } }$
  3. C $\mathrm { d } \overrightarrow { \mathrm { B } } = \frac { \mu _ { 0 } } { 4 \pi } \frac { \mathrm { i } \overrightarrow { \mathrm { d } } \ell \times \hat { \mathrm { r } } } { \mathrm { r } ^ { 3 } }$
  4. D $\mathrm { d } \overrightarrow { \mathrm { B } } = \frac { \mu _ { 0 } } { 4 \pi } \frac { \mathrm { i } \overrightarrow { \mathrm { d } } \ell \times \overrightarrow { \mathrm { r } } } { \mathrm { r } ^ { 2 } }$
Show answer

Correct answer: B

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 2 20 Q Magnetic Effects of Current and Magnetism — DPP 3 20 Q
All Magnetic Effects of Current and Magnetism tests →