Current Electricity

The resistance of an incandescent lamp is

• smaller when switched on

• greater when switched off

• the same whether it is switch off or switch on

• greater when switched on

An ammeter and a voltmeter are joined in series to a cell. Their readings are A and V respectively. If a resistance is now joined in parallel with the voltmeter, then

• A will decrease, V will increase

• A will increase, V will decrease

• both A and V will increase

• both A and V will decrease

If each of the resistance of the network shown in figure is R, the equivalent resistance between A and B is

• 3R

• 5R

• $\frac{\mathrm{R}}{2}$

• R

A cell supplies a current of 0.9 A through a 2 Ω resistor and a current of 0.3 A through a 7 Ω resistor. The internal resistance of the cell is

• 1.2 Ω

• 2.0 Ω

• 0.5 Ω

• 1.0 Ω

A and B are two conductors carrying a current I in the same direction. x and y are two electron beams moving in the same direction. Then there will be

• attraction between A and B, repulsion between x and y

• repulsion between A and B, attraction between x and y

• attraction between A and B and x and y

• repulsion between A and B and x and y

The current-voltage graph for a given metallic conductor at two different temperature T₁ and T₂ are as shown in the figure. Then

• T₁ < T₂

• nothing can be said about T₁ and T₂

• T₁ = T₂

• T₁ > T₂

The current-voltage graph for a given metallic conductor at two different temperature T₁ and T₂ are as shown in the figure. Then

• T₁ < T₂

• nothing can be said about T₁ and T₂

• T₁ = T₂

• T₁ > T₂