Question

A semicircular conducting ring of radius R is placed in the xy plane, as shown in the figure. A uniform magnetic field is set up along the X-axis. No net EMF will be induced in the ring, if

• A. it moves along the X-axis
• B. it moves along the Y-axis
  
• C. it moves along the Z-axis
• D. it remains stationary
  

Answer 1

Answer: (A), (B), (C), (D)

it remains stationary


EMF induced (by Lenz's law),
$E=-\frac{d\varphi }{dt}$
$E=-\frac{d\left(BA\right)}{dt}$=$-B\frac{d\left(A\right)}{dt}$ $-A\frac{d\left(B\right)}{dt}$
Either magnetic field or area must be changed with respect to time to generate emf and here, positive magnetic field and plane of ring are parallel.
There is no magnetic field along Y and Z axis, hence change in magnetic field is zero and emf along Y and Z axis is $0$
Therefore, the correct answer is (A,B,C,D).