A thin semicircular conducting ring (PQR) of radius r is falling with its plane vertical in a horizontal magnetic field B, as shown in the figure.


The potential difference developed across the ring when its speed is $$v$$, is

A current of 2.5 A flows through a coil of inductance 5 H. The magnetic flux linked with the coil is

A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced e.m.f. is

In a coil of resistance 10 $$\Omega $$, the induced current developed by changing magnetic flux through it, is shown in figure as a function of time. The magnitude of change in flux through the coil in weber is