Question

A rectangular loop PQRS, is being pulled with constant speed into a uniform transverse magnetic fieldby a force F (as shown). E.m.f. induced in side PS and potential difference between points P and S respectively are (Resistance of the loop = r)

• A. Zero, $\frac{Fr}{B\ell }$
• B. Zero, zero
• C. Zero , $\frac{Fr}{6B\ell }$
• D. $\frac{Fr}{6B\ell },\frac{Fr}{6B\ell }$

Answer 1

The correct option is C Zero , $\frac{Fr}{6B\ell }$

No Emf is induced over side PS since it does not lie inside the magnetic field.

Since the loops is pulled at constant speed under force F, this force must be balancing the force on the current carrying wire due to magnetic field.

$⟹F=Bil$

$⟹i=\frac{F}{Bl}$

The current goes through side PS causing a potential difference of

$i{R}_{PS}$

$=i\frac{r}{6}$

$=\frac{Fr}{6Bl}$