A heating coil is labelled 100 W, 220 V. The coil is cut in two equal- halves and the two pieces are joined in parallel to the same source. The energy now liberated per second is
25 J
50 J
200 J
400 J
A 4µF capacitor is charged to 400 V and then its plates are joined through a resistance of 1 kΩ. The heat produced in the resistance is
0.16 J
1.28 J
0.64 J
0.32 J
Two identical batteries each of emf 2 V and internal resistance 1 Ω are available to produce heat in an external resistance by passing a current through it. The maximum power that can be developed across R using these batteries
3.2 W
2.0 W
1.28 W
If nearly 105 C liberate 1g equivalent of aluminium, then the amount of aluminium (equivalent weight 9) deposited through electrolysis in 20 min by a current of 50 A will be
0.6 g
0.09 g
5.4 g
10.8 g
A battery of emf 10 V internal resistance 0.5Ω is connected across a variable resistance R. The value of R for which the power delivered in it is maximum is given by
0.5 Ω
1.0 Ω
2.0 Ω
0.25 Ω
Three equal resistors connected in series across a source of emf together dissipate 10 W of power. What will be the power dissipated in watt if the same resistors are connected in parallel across the same source of emf?
W
10W
30W
90W
Two bulbs 25 W, 220 V and 100 W, 220 V are given. Which has higher resistance?
25 W bulb
100 W bulb
Both bulbs will have equal resistance
Resistance of bulbs cannot be compared
In producing chlorine through electrolysis 100 W power at 125 V is being consumed. How much chlorine per minute is liberated ? (ECE of chlorine is 0.367 x 10-6 kg/C)
17.6 mg
21.3 mg
24.3 mg
13.6 mg
In India electricity is supplied for domestic use at 220V.It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is R, the resistance of a 60 W bulb for use in USA will be
R
2R
A 100 W - 200 V bulb is connected to a 160 V power supply. The power consumption would be
125 W
100 W
80 W
64 W
