NEET Physics Biot Savarts Law and Amperes Circuital Law MCQs Set A

Question. The magnetic field around a long straight current carrying wire is
(a) unsymmetrical
(b) cylindrical symmetry
(c) spherical symmetry
(d) cubical symmetry

Answer: A

Question. If a copper rod carries a direct current, the magnetic field associated with the current will be
(a) both inside and outside the rod
(b) neither inside nor outside the rod
(c) only outside the rod
(d) only inside the rod

Answer: A

Question. If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be
(a) only outside the pipe
(b) neither inside nor outside the pipe
(c) both inside and outside the pipe
(d) only inside the pipe

Answer: A

Question. Energy in a current carrying coil is stored in the form of
(a) magnetic field
(b) heat
(c) electric field
(d) dielectric strength

Answer: A

Question.  Which of the following statements is/are correct?
I. The magnetic field in the open space inside the toroid is constant.
II. The magnetic field in the open space exterior to the toroid is constant.
III. The magnetic field inside the core of toroid is constant.
(a) I only
(b) II and III
(c) I and II
(d) III only

Answer: A

Question. Assertion : If the current in a solenoid is reversed in direction while keeping the same magnitude, the magnetic field energy stored in the solenoid decreases.
Reason : Magnetic field energy density is proportional to square of current.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: A

Question. A current I flows along the length of an infinitely long, straight, thin walled pipe. Then
(a) the magnetic field at any point inside the pipe is zero
(b) the magnetic field is different at different points inside the pipe
(c) the magnetic field at all points inside the pipe is the same, but not zero
(d) the magnetic field is zero only on the axis of the pipe

Answer: A

Question. A long straight wire in the horizontal plane carries a current of 75 A in north of south direction, magnitude and direction of field B at a point 3 m east of the wire is
(a) 5 × 10^–6 T, vertical up
(b) 4 × 10^–6 T, vertical down
(c) 5 × 10^–6 T, vertical down
(d) 4 × 10^–6 T, vertical up

Answer: A

Question. A circular coil of wire consisting of 100 turns each of radius 9 cm carries a current of 0.4 A. The magnitude of manetic field at the centre of the coil is
(a) 2.79 × 10^–4 T
(b) 2.4 × 10^–4 T
(c) 3.5 × 10^–4 T
(d) 3 × 10^–4 T

Answer: A

Question. A solenoid of length 0.6 m has a radius of 2 cm and is made up of 600 turns If it carries a current of 4 A, then the magnitude of the magnetic field inside the solenoid is
(a) 5.024 × 10^–3 T
(b) 6.024 × 10^–3 T
(c) 8.024 × 10^–3 T
(d) 7.024 × 10^–3 T

Answer: A

Question. A long solenoid carrying a current produces a magnetic field B along its axis. If the current is double and the number of turns per cm is halved, the new value of the magnetic field is
(a) B
(b) 2 B
(c) B/2
(d) 4 B

Answer: B

Question. If we triple the radius of a coil keeping the current through it unchanged, then the magnetic field at any point at a large distance from the centre becomes approximately how much times ?
(a) 4
(b) 3
(c) 8
(d) 9

Answer: A

Question. The magnetic induction at a point P which is at a 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
(a) 3.33 × 10^–4 T
(b) 3 × 10^–3 T
(c) 1.11 × 10^–4 T
(d) 9 × 10^–3 T

Answer: A