A semicircular wire of radius R is rotated with constant angular velocity $\mathrm{\omega }$ about an axis passing through one end and perpendicular to the plane of the wire.

There is a uniform magnetic field of strength B. The induced emf between the ends is -

1. ${\mathrm{B\omega R}}^{2}/2$

2. $2{\mathrm{B\omega R}}^{2}$

3. is variable

4. none of these

Concept Questions :-

Motional emf
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The inductance of a closed-packed coil of 400 turns is 8 mH. A current of 5 mA is passed through it. The magnetic flux through the coil is approximately

1.

2.

3.

4.

Concept Questions :-

Self-inductance
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Loop A of radius (r << R) moves towards loop B with a constant velocity v in such a way that their planes are always parallel.

What is the distance (x) between the two loops when the induced emf in loop A is maximum –

1. $\mathrm{R}$

2. $\frac{\mathrm{R}}{\sqrt{2}}$

3. $\frac{\mathrm{R}}{2}$

4. $\mathrm{R}\left(1-\frac{1}{\sqrt{2}}\right)$

Concept Questions :-

Motional emf
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The current in an L – R circuit builds up to ${\left(3/4\right)}^{\mathrm{th}}$ of its steady state value in 4 seconds. The time constant of this circuit is

1.

2.

3.

4.

Concept Questions :-

LR circuit
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The magnetic flux through each turn of a 100 turn coil is , where t is in second. The induced emf at t = 2 s is

1.

2.

3.

4.

Concept Questions :-

Faraday 's law and lenz law
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An emf of 15 volt is applied in a circuit containing 5 henry inductance and 10 ohm resistance. The ratio of the currents at time t = $\infty$ and at t = 1 second is -

1.  $\frac{{\mathrm{e}}^{1/2}}{{\mathrm{e}}^{1/2}-1}$

2.  $\frac{{\mathrm{e}}^{2}}{{\mathrm{e}}^{2}-1}$

3.  $1-{\mathrm{e}}^{-1}$

4.  ${\mathrm{e}}^{-1}$

Concept Questions :-

LR circuit
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A circular coil of radius 5 cm has 500 turns of a wire. The approximate value of the coefficient of self induction of the coil will be -

1.

2.

3.

4.

Concept Questions :-

Self-inductance
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A coil of radius 1 cm and  turns 100 is placed in the middle of a long solenoid of radius 5 cm and having 8 turns/cm. The mutual induction in millihenry will be-

1.  0.0316

2.  0.063

3.  0.105

4.  Zero

Concept Questions :-

Mutual-inductance
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides.

A magnetic induction B, constant in time and space, pointing perpendicular and into the plane of the loop exists everywhere, see figure. The current induced in the loop is

1.  BLv/R clockwise

2.  BLv/R anticlockwise

3.  2 BLv/R anticlockwise

4.  zero

Concept Questions :-

Motional emf
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A copper rod of length 0.19 m is moving parallel to a long wire with a uniform velocity of 10 m/s. The long wire carries 5 ampere current and is perpendicular to the rod. The ends of the rod are at distances 0.01 m and 0.2 m from the wire. The emf induced in the rod will be-

1.

2.

3.

4.

Concept Questions :-

Motional emf