The diagram shows a circuit having a coil of resistance `R=10Omega` and inductance L connected to a conducting rod PQ which can slide on a perfectly conducting circular ring of radius 10 cm with its centre at 'P' Assume that friction & gravity are absent and a constant uniform magnetic field of 5 T exists as shown in figure. At `t=0` the circuit is switched on and simultaneously a time varying external torque is applied on the rod so that it rotates about P with a constant angular velocity 40 rad//s Find magnitude of this torque (in mu Nm) when current reaches half of its maximum value. Neglect the self inductance of the loop formed by the circuit.

The diagram shows a circuit having a coil of resistance R = 2.5 (Omega) and inductance L connected to a conducting rod PQ which can slide on perfectly conducting circular ring of radius 10 cm with its centre at 'P'. Assume that friction and gravity are absent and a constant uniform magnetic field of 5 T exist as shown in Fig. At t = 0, the circuit is switched on and simultaneously a time varying external torque is applied on the rod so that it rotates about P with a constant angular velocity 40 rad//s . Find magnitude of this torque (in milli Nm) when current reaches half of its maximum value. Neglect the self-inductance of the loop formed by the circuit.

Figure shows a circuit having a coil of resistance R = 2.5 Omega and inductance L connected to a conducting rod of radius 10 cm with its center at P . Assume that friction and gravity are absent and a constant uniform magnatic field of 5 T exists as shown in figure. At t = 0 , the circuit is switched on and simultaneously a time-varying external torque is applied on the rod so that it rotates about P with a constant angular velocity 40 rad s^(-1) . Find the magnitude of this torque (in mNm ) when current reaches half of its maximum value. Neglect the self inductance of the loop formed by the circuit.

The circuit shows a resistance, R=0.01Omega and inductance L=3mH connected to a conducting rod PQ of length l=1m which can slide on a perfectly conducting circular arc of radius l with its center at P. Assume that friction and gravity are absent and a constant uniform magnetic field b=0.1T exists as shown in the figure. At t=0, the circuit is seitched on a simultaneously an external torque is applied on the rod so that it rotates about P with a constant angular velocity omega =2 rad//sec . Find the magnitude of this torque (inN-m) at t=(0.3In 2) second.

A resitance R=1kOmega connected to a conducting rod PQ that can slide on a conducting circular ring of radius 2m with center at P . A constant uniform magnetic field 10 Tesla exist as shown in figure. At t=0 , switch 'S' is closed and simulaneously an external torque is applied on the rod so that it rotates with constant angular velocity 20"rad"//"sec" . The magnitude of power delivered by external is 20K Watt. Find the value of K . (Neglect the gravity, friction and self inductance of circular loop)