A magnet is moving towards a coil along its axis and the emf induced in the coil is `epsilon`. If the coil also starts moving towards the magnet with the same speed, the induced emf will be ____

Options

A. `epsilon/2`
B. `epsilon`
C. `2epsilon`
D. `4epsilon`

Answer

C

Explanation

Induced emf =Bvl (value)
`therefore emf_1 prop v` where v is relative velocity [ `because` B and l are constant]
Here when relative velocity becomes 2v, the induced `emf_2 prop 2v`,
`therefore (emf_2)/(emf_1)=(2v)/v`
`therefore emf_2=2xxemf_1`
`therefore emf_2=2 epsilon " " [ because emf_1=epsilon]`