A group of devices having a total power rating of 500 watt is supplied by an $$\mathrm{AC}$$ voltage $$E=200 \sin \left(3.14 t+\frac{\pi}{4}\right)$$. Then the r.m.s. value of the circuit current is
$$ \text { In a p-n junction, the depletion layer of thickness } 1 \mu \mathrm{m} \text { has } 0.05 \mathrm{~V} \text { potential across it. The electric field in } N C^{-1} \text { is } $$
A long horizontal wire $$\mathrm{P}$$ carries current of $$50 \mathrm{~A}$$ from left to right. It is rigidly fixed. Another fine wire $$\mathrm{Q}$$ is placed directly above and parallel to $$\mathrm{P}$$. The mass of the wire is '$$\mathrm{m}$$' $$\mathrm{kg}$$ and carries a current of '$$\mathrm{I}$$' A. The direction of current in $$\mathrm{Q}$$ and position of wire $$\mathrm{Q}$$ from $$\mathrm{P}$$ so that the wire $$\mathrm{Q}$$ remains suspended are
A record player is spinning at an angular velocity of $$45 \mathrm{~rpm}$$ just before it is turned off. It then decelerates at a constant rate of $$0.8 \mathrm{~rad} \mathrm{~s}^{-1}$$. The angular displacement is