Question

A $10m$ long horizontal wire extends from North East to South West. It is falling with a speed of $5.0m{s}^{-1}$, at right angles to the horizontal component of the earth's magnetic field, of $0.3\times {10}^{-4}Wb/m^2$. The value of the induced emf in wire is:

• A. $2.5\times {10}^{-3}V$
• B. $1.1\times {10}^{-3}V$
• C. $0.3\times {10}^{-3}V$
• D. $1.5\times {10}^{-3}V$

Answer 1

Answer: (B)

$1.1\times {10}^{-3}V$

Induced emf $=Bv\ell sin45$
$=0.3\times {10}^{-4}\times 5\times 10\times \frac{1}{\sqrt{2}}$
$=1.1\times {10}^{-3}V$