Questions in Alternating Current

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	For an ac circuit $V = 15\sin \omega t$ and $I = 20\cos \omega t$ the average power consumed in this circuit is
	A bulb is connected first with dc and then ac of same voltage then it will shine brightly with
	An ac supply gives 30 V r.m.s. which passes through a 10$\Omega $ resistance. The power dissipated in it is
	The frequency of an alternating voltage is 50 cycles/sec and its amplitude is 120V. Then the r.m.s. value of voltage is
	A resistance of 20 ohms is connected to a source of an alternating potential $V = 220\sin (100\pi t)$. The time taken by the current to change from its peak value to r.m.s value is
	Voltage and current in an ac circuit are given by $V = 5\sin \,\left( {100\pi t - \frac{\pi }{6}} \right)$ and $I = 4\sin \,\left( {100\pi t + \frac{\pi }{6}} \right)$
	If an ac main supply is given to be $220 V$. What would be the average e.m.f. during a positive half cycle
	In an ac circuit, the r.m.s. value of current, $I_rms$ is related to the peak current, I0 by the relation
	An alternating voltage is represented as $E = 20\sin 300t.$ The average value of voltage over one cycle will be
	The ratio of peak value and r.m.s value of an alternating current is