Question

A conducting square loop is placed in a transverse magnetic field $B$. The sides of the square start shrinking at the constant rate $\alpha$. The induced emf in the loop at an instant when its side is a :-

• A. $2a\alpha B$
• B. $a^2\alpha B$
• C. $2a^2\alpha B$
• D. $a\alpha B$

Answer 1

The correct option is C $2a^2\alpha B$

A horizontal force$=F$

Mass=m

width=b

Height=H

The block moves with constant velocity the coefficient of friction ${\mu }_k$

A conducting square loop is placed in a transverse magnetic field $=B$

The sides of the square start shrinking at the constant $=a$

The induced emf in the loop at an instant when its sides is a

$Emf=2a^2\alpha B$

Due to the Faraday's law

$Emf=-N\frac{d\varphi }{dt}=2a^{2}B\times \alpha =2a^2\alpha B$