Question

A horizontal straight wire $20m$ long extending from east to west is falling with a speed of $5.0m/s$ at right angle to the horizontal component of the earths magnetic field $0.30\times {10}^{-4}Wb/m^2$. The instantaneous value of the e.m.f induced in the wire will be

• A. $1.5mV$
• B. $6.0mV$
• C. $3mV$
• D. $4.5mV$

Answer 1

The correct option is C $3mV$

C. $3mV$

Given,

$B=0.30\times {10}^{-4}Wb/m^2$

$l=20m$

$v=5.0m/s$

The instantenous value of the emf induced in the wire is.

$\epsilon =Bvl$

$=0.30\times {10}^{-4}\times 5\times 20V$

$\epsilon =3mV$