A storage battery is connected to the mains for charging with emf of 12.5 V. The internal resistance of the storage battery is 1 Ω. When the charging current is 0.5 A, the potential difference across the storage battery is
13 V
12.5 V
12 V
11.5 V
A piece of copper and another of germanium are cooled from room temperature to 80K.The resistance of
each of them increases
each of them decreases
copper increases and germanium decreases
copper decreases and germanium increases
A 10 metre potentionmeter wire has a resistance of 20 Ω. It is connected in series with a battery of emf 2.5 volt and a resistance of 5 Ω. The potential gradient along wire in volt cm-1 is
0.002
0.02
0.2
0.0025
Four bulbs marked 40 W, 250 V are connected in series with 250 V mains, the total power consumed is
10 W
40 W
320 W
160 W
Kirchhoff's current law at a junction deals with conservation of
charge
energy
momentum
all of these
The negative Zn pole of a Daniell cell, sending a contant current through a circuit, decreases in mass by 0.13 g in 30 minutes. If the electrochemical equivalent of Zn and Cu are 32.5 and 31.5 respectively, the increase in the mass of the positive Cu pole in this time is
0.180 g
Iron and silicon wires are heated from 30°C to 50°C.The correct statement is that
resistance of both the wires increases
resistance of both the wires decreases
resistance of iron wire increases and that of silicon wire decreases
resistance of iron wire decreases and that of silicon wire increases
A 2 kW boiler used for 1 hour everyday consumes electrical energy in thirty days equal to
120 units
60 units
15 units
30 units
Two inductors each of inductance L are connected in parallel. What is their equivalent inductance?
2L
L
L/2
L/4
