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
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
Direct current is passed through a copper sulphate solution using platinum electrodes. The elements liberated at the electrodes are
Copper at anode and sulphur at cathode
Sulphur at anode and copper at cathode
Oxygen at anode and copper at cathode
Copper at anode and oxygen at cathode
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
Two 220 V, 100 W bulbs are connected first in series and then in parallel. Each time the combination is connected to a 220 V AC supply line. The power drawn by the combination in each case respectively will be
200 W, 150 W
50 W, 200 W
50 W, 100 W
100 W, 50 W
Power dissipated across the 8Ω resistor in the circuit shown here is 2 W. The power dissipated in watt units across the 3Ω resistor is
2.0
1.0
0.5
3.0
A steady current of 1.5 A flows through a copper voltameter for 10 min. If the electrochemical equivalent of copper is 30 x 10-5 g C-1 the mass of copper deposited on the electrode will be
0.40 g
0.50 g
0.67 g
0.27 g
A 5 A fuse wire can withstand a maximum power of 1 W in a circuit. The resistance of the fuse wire is
0.2 Ω
5 Ω
0.4 Ω
0.04 Ω
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
