A copper disc of radius 10 cm is rotating in magnetic field B = 0.4 gauss with 10 rev./sec. What will be potential difference across peripheral points of disc?

• A

  20$\mathrm{\pi }$uV

• B

  10$\mathrm{\pi }$uV

• C

  zero

• D

  5$\mathrm{\pi }$uV