JEE Physics - MCQ Practice Questions

A parallel plate capacitor is filled with a dielectric of dielectric constant κ. How does this affect the capacitance compared to vacuum?

A uniformly charged infinite line with linear charge density λ = 2 × 10⁻⁸ C/m is placed along the z-axis. A point charge q = +1 μC is located at a perpendicular distance r = 0.1 m from the line. The electric field due to the line charge at the location of the point charge is perpendicular to the line. If the permittivity of free space is ε₀ = 8.85 × 10⁻¹² F/m, calculate the magnitude of the electric field at the point charge location.

Two identical conducting spheres A and B have charges +Q and +3Q respectively. They are separated by a distance much larger than their radii. When brought into contact and then separated to the original distance, the electrostatic force between them changes by a factor of:

In a balanced Wheatstone bridge, if the resistance of one arm is changed by 10%, by what percentage should another arm be changed to maintain balance?

A battery of EMF 12V with internal resistance 2Ω is connected to an external resistance of 4Ω. What is the terminal voltage?

A metallic conductor's resistance increases with temperature. This is primarily because:

A heating element rated 1000W, 200V is connected to a 100V supply. The heat generated will be:

In a meter bridge, the null point is found at 60cm from left. If a standard resistance of 15Ω is on the right, the unknown resistance is:

A copper wire of diameter 1 mm carries a current of 5 A. If the drift velocity of electrons is 0.5 mm/s, find the number density of free electrons in copper. (Given: e = 1.6 × 10⁻¹⁹ C)

A potential divider uses a 100 cm wire of total resistance 10Ω. A cell of EMF 2V and negligible internal resistance is connected across it. What is the potential gradient along the wire?

A battery of EMF E and internal resistance r is connected to an external resistance R. The terminal voltage is:

In a potentiometer, if the balancing length for a cell is 60 cm and for standard cell is 50 cm, what is the EMF of the unknown cell? (Standard cell = 1.018V)

A galvanometer with coil resistance 100Ω shows full-scale deflection at 10 mA. What shunt resistance is needed to convert it into an ammeter reading up to 1 A?

A rectangular conductor with dimensions 2cm × 3cm × 10cm is placed such that current flows through the 10cm length. If resistivity is 1.7 × 10⁻⁸ Ω·m, find the resistance:

A copper wire of length L and cross-sectional area A has resistance R. If the wire is stretched to double its length while maintaining the same volume, what is the new resistance?

A wire of resistance 5Ω is bent into a square loop. What is the equivalent resistance between two adjacent corners?

In a Wheatstone bridge at balance, if P = 10Ω, Q = 20Ω, and R = 15Ω, then S equals:

Two resistors R₁ and R₂ are connected in series with a battery. If R₁ = 2R₂ and the voltage across R₁ is 8V, the voltage across R₂ is:

In a potentiometer experiment, the balancing length for a cell of EMF E is 75 cm. If another cell of EMF E/2 is used, the balancing length would be:

The EMF of a cell is 2V and its internal resistance is 0.5Ω. When connected to external resistance, the terminal voltage is 1.8V. The current in the circuit is: