A thin semicircular conducting ring (PQR) of radius 'r' is falling with its plane vertical in a horizontal magnetic field…

A thin semicircular conducting ring (PQR) of radius 'r' is falling with its plane vertical in a horizontal magnetic field B, as shown in figure. The potential difference developed across the ring when its speed is v, is:
A Zero
B $\frac{Bv\pi r^2}{2}$ and P is at higher potential
C $\pi rBv$ and R is at higher potential
D 2rBv and R is at higher potential

Detailed Solution


The semicircular ring is equivalent to a straight conductor PR of length 2r moving with speed v.
Induced emf $= Bv(2r) = 2rBv$, with R at the higher potential.

Motional emf in past papers

3 questions from this chapter have appeared across 3 exam years.

Keep going

Practise Motional emf All 3 questions This chapter in 2014 AIPMT