NEET Physics Electromagnetic Induction MCQs

a)

b)

c)

d)

Answer:

Question: A cylindrical bar magnet is rotated about its axis. A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then,
a) no current flows through the ammeter A
b) None of these
c) a direct current flows in the ammeter A
d) a time varying non-sinusoidal current flows through the ammeter A.
Answer: no current flows through the ammeter A

Question:

a)

b)

c) Both
d) None of these

Answer:

Question: A thin semicircular conducting ring (PQR) of radius ‘r’ is falling with its plane vertical in a horizontal magnetic field B, as shown in figure. The potential difference developed across the ring when its speed is v, is :

a) 2rBv and R is at higher potential
b) Zero
c) Both
d) None of these
Answer:  2rBv and R is at higher potential

Question:

a) –10 V
b) 10 V
c) 190 V
d) –190 V
Answer: –10 V

Question:  Assertion : Lenz's law violates the principle of conservation of energy.
Reason : Induced emf always opposes the change in magnetic flux responsible for its production
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:  Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question: An electron moves on a straight line path XY as shown. The abcd is a coil adjacent to the path of electron. What will be the direction of current if any, induced in the coil?

a) The current will reverse its direction as the electron goes past the coil
b) No current induced
c) abcd
d) None of these
Answer: The current will reverse its direction as the electron goes past the coil

Question: In generator, having a coil with N turns, all of the same area A and total resistance R, rotates with frequency w in a magnetic field B. The maximum value of emf generated in the coil is

a)

b)

c) N.A.B.
d) N.A.B.R.
Answer:

Question:

a)

b)

c)

d) None of these

Answer:

More Questions.....................................

Question: A long solenoid has 1000 turns. When a current of 4A flows through it, the magnetic flux linked with each turn of the solenoid is 4 × 10^–3 Wb. The self inductance of the solenoid is :
a) 1H
b) 2H
c) 3H
d) 4H
Answer: 1H

Question: In an inductor of self-inductance L = 2 mH, current changes with time according to relation i = t²e^–t. At what time emf is zero?
a) 2s
b) 1s
c) 3s
d) 4s
Answer: 2s

Question:  A conducting circular loop is placed in a uniform magnetic field of 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced emf in the loop when the radius is 2 cm is
a)

b)

c)

d) None of these

Answer:

Question:

a)

b)

c)

d) None of these

Answer:

Question:  A conducting rod AB moves parallel to X-axis in a uniform magnetic field, pointing in the positive X-direction. The end A of the rod gets

a) positively charged
b) negatively charged
c) neutral
d) first positively charged and then negatively charged
Answer:  positively charged

Question:

a) 250 Wb
b) 275 Wb
c) 200 Wb
d) 225 Wb
Answer: 250 Wb

Question:  A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil it starts oscillating; It is very difficult to stop. But if an aluminium plate is placed near to the coil, it stops. This is due to :
a) electromagnetic induction in the aluminium plate giving rise to electromagnetic damping
b) shielding of magnetic lines of force as aluminium is a paramagnetic material
c) induction of electrical charge on the plate
d) developement of air current when the plate is placed
Answer: electromagnetic induction in the aluminium plate giving rise to electromagnetic damping

Question: The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance
a) 13.89 H
b) 138.88 H
c) Both
d) 1.389 H
Answer: 13.89 H

Question: Assertion : In the phenomenon of mutual induction, self induction of each of the coil persists.
Reason : Self induction arises due to change in current in the coil itself. In mutual induction current changes in both the individual coil.
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:  Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question:

a)

b)

c)

d) None of these
Answer:

Question:

a)

b)

c)

d) 0

Answer:

Question:

a)

b)

c)

d) None of these

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d) zero

Answer:

Question:

a)

b)

c)

d) None of these

Answer:

Question:

a)

b)

c)

d) zero

Answer:

Question:

a)

b)

c)

d) None of these
Answer:

Question:  In a uniform magnetic field of induction B a wire in the form of a semicircle of radius r rotates about the diameter of the circle with an angular frequency w. The axis of rotation is perpendicular to the field. If the total resistance of the circuit is R, the mean power generated per period of rotation is

a)

b)

c)

d) None of these
Answer:

Question:

a) 1 mV
b) 1 volt
c) 10 mV
d) 10^–2 volt
Answer: 1 mV

Question:  A conducting square frame of side ‘a’ and a long staight wire carrying current I are located in the same plane as shown in the figure. The frame moves to the right with a constant velocity ‘V’. The emf induced in the frame will be proportional to

a)

b)

c) Both
d) None of these
Answer:

Question:

a) 2 Blv
b) zero
c) Blv
d) – Blv
Answer: 2 Blv