Questions in Current Electricity

Select	Question
	If resistance of voltmeter is 10000$\Omega$ and resistance of ammeter is 2$\Omega$ then find R when voltmeter reads 12V and ammeter reads 0.1 A
	Potentiometer wire of length 1 m is connected in series with 490$\Omega $ resistance and 2V battery. If 0.2 mV/cm is the potential gradient, then resistance of the potentiometer wire is
	One kilowatt hour is equal to
	If ${R_1}$ and ${R_2}$ are respectively the filament resistances of a 200 watt bulb and 100 watt bulb designed to operate on the same voltage, then
	Two electric bulbs, one of 200 volt 40 watt and the other 200 volt 100 watt are connected in a house wiring circuit
	The two bulbs as in the above question are connected in series to a 200 volt line. Then
	Forty electric bulbs are connected in series across a 220 V supply. After one bulb is fused, the remaining 39 are connected again in series across the same supply. The illumination will be
	The material of fuse wire should have
	Two electric bulbs whose resistances are in the ratio of $1 : 2$ are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio
	A heater coil is cut into two parts of equal length and one of them is used in the heater. The ratio of the heat produced by this half coil to that by the original coil is