JEE Physics - MCQ Practice Questions

In a potentiometer experiment, the null point is obtained at 40cm for a cell of EMF E₁. When a resistance of 5Ω is connected in series with the cell, the null point shifts to 30cm. The internal resistance of the cell is:

The sensitivity of a galvanometer can be increased by:

A wire of length L and cross-sectional area A has resistance R. If the wire is stretched to length 2L without change in volume, the new resistance will be:

The equivalent resistance between two opposite corners of a cube made of 12 wires of 1Ω each is:

A heating element of resistance R is connected to a battery of EMF E and internal resistance r. Maximum power is dissipated in R when:

Which of the following best explains why semiconductor resistance decreases with increase in temperature?

A battery of EMF 12V and internal resistance 2Ω is connected to a load resistance R. For maximum power transfer, R should be:

The electric field inside a copper conductor carrying current is approximately:

When a superconductor is cooled below its critical temperature, its resistance becomes zero. What is the effect on current flowing through it when connected to a constant voltage source?

The length of a conductor increases by 10% when stretched. Assuming volume remains constant, the resistance increases by approximately:

The equivalent resistance of an infinite ladder network of 1Ω resistors (each rung) is:

A superconductor exhibits zero resistance below its critical temperature because:

In a Wheatstone bridge, arms P, Q, R, and S have resistances 10Ω, 15Ω, 20Ω, and 30Ω respectively. A galvanometer is connected between junctions of P-Q and R-S. The galvanometer reading will be: