Question

Swastick shown in figure is rotating at angular velocity of $\omega$ about O in a uniform magnetic field B perpendicular to the plane of the paper. Here, oa = oe = og = hg = ab = oc = cd = ef = L.

• A. Potential difference between a and e is $2B\omega L^2$
• B. Potential difference between a and c is $B\omega L^2$
• C. Potential difference between b and e is $\frac{B\omega L^2}{2}$
  
• D. Potential difference between e and g is zero

Answer 1

Answer: (C), (D)

The correct options are
C Potential difference between b and e is $\frac{B\omega L^2}{2}$

D Potential difference between e and g is zero

Potential of points a, c, e and g is $\frac{B\omega l^2}{2}$ & Potential of points b, d, f and h is $B\omega L^2$.
So, potential difference across ae and ag = 0 and,
Hence, potential difference across ab = $B\omega L^2-\frac{B\omega L^2}{2}=\frac{B\omega L^2}{2}.$