## A conducting rod moves perpendicularly through a uniform magnetic field. How does the emf change if the magnetic field is increased by a fac

A conducting rod moves perpendicularly through a uniform magnetic field. How does the emf change if the magnetic field is increased by a factor of 4 and the time required for the rod to move through the field is decreased to half of the original time?

a) It increases by a factor of 2

b) It increases by a factor of 4

c) It increases by a factor of 8

d) It increases by a factor of 16 .

## Answers ( )

Answer:c) It increases by a factor of 8

Explanation:According to

Faraday’s law (and Lenz’ law), theinduced EMF is given as the rate of change of magnetic flux.Mathematically:

V = -dФ/dt

Magnetic flux, Ф, is given as:

Ф = BA

where B = magnetic field strength and A = Area of object

Hence, induced EMF becomes:

V = -d(BA)/dt or -BA/t

If the

magnetic field is increased by a factor of 4, () and thetime required for the rod to move is decreased by a factor of 2(), the induced EMF becomes:The EMF has increased by a factor of 8.