Question

1. A magnet is inserted into a coil of wire consisting of 10000 loops. The cross-sectional area of the coil is 0.5 m²and is kept in a uniform magnetic field of B = 4 T. Assume that the angle between the surface normal of the coil and magnetic field is q_o= 45^oat t₀= 0s. The coil is rotated at a constant rate to an angle, q= 90⁰at t = 60s. What is the average induced voltage (emf) induced in the coil?

A) 177 V        B) 220 V         C) 288.70 V    D) 235.70 V

2. To have stationary interference pattern in young double slit experiment, wavelength of incident beams should be:

A) Same         B) different      C) zero D) Infinite

3. If we switch from red laser (l= 670nm) to green laser (l= 530nm) in a Young’s double slit diffraction experiment then what happens to the fringe pattern?

A) Nothing     B) Position of the Principle maxima changed by 130 nm.

C) Separation between fringes increases.       D) Separation between fringes decreases

Answer 1

1)

Magnetic flux

EMF induced in the coil is

Average emf induced in the coil is

2) To have a stationary interference pattern in young double slit experiment, the waves must have same frequence and must be in phase. So the waves have same wavelength.

Answer is A) Same

3) Fringe width ( for red light ) , ( for green light )

Fringe width is the seperation between two neighbouring maxima.

as , fringe width for the green light decreases.

That is seperation between the fringes decreases.

Answer is D) Seperation between the fringes decreases.