A straight wire is placed in a magnetic field that varies with distance x from origin as $$\overrightarrow B = {B_0}\left( {2 - {x \over a}} \right)\widehat k$$. Ends of wire are at (a, 0) and (2a, 0) and it carries a current I. If force on wire is $$\overrightarrow F = I{B_0}\left( {{{ka} \over 2}} \right)\widehat j$$, then value of k is
In a closed circuit there is only a coil of inductance L and resistance 100 $$\Omega$$. The coil is situated in a uniform magnetic field. All on a sudden, the magnetic flux linked with the circuit changes by 5 Weber. What amount of charge will flow in the circuit as a result?
When an AC source of emf E with frequency $$\omega$$ = 100 Hz is connected across a circuit, the phase difference between E and current I in the circuit is observed to be $${\pi \over 4}$$ as shown in the figure. If the circuit consist of only RC or RL in series, then
A battery of emf E and internal resistance r is connected with an external resistance R as shown in the figure. The battery will act as a constant voltage source if