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
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
In a potentiometer of 10 wires, the balance point is obtained on the 7th wire. To shift the balance point to 9th wire, we should
decrease resistance in the main circuit
increase resistance in series with circuit
decrease resistance in series with the cell whose emf is to be measured
increase resistance in series with the cell whose emf is to be determine
Kirchhoff's current law at a junction deals with conservation of
charge
energy
momentum
all of these
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
The length of a potentiometer wire is 5 metres. An electron in this wire experiences a force of 4.8 × 10-19 newton, emf of the main cell used in potentiometer is
3 volt
15 volt
1.5 volt
5 volt
In a potentiometer of 10 wires,the balance point is obtained on the 7th wire.To shift the balance point to 9th wire,we should
increase resistance in the main circuit
increase resistance in series with the cell whose emf is to be determined
