JEE Physics - MCQ Practice Questions
Physics is where JEE ranks are usually won or lost, since a single conceptual slip changes the whole answer. Questions here span mechanics, rotational motion, thermodynamics, waves and oscillations, electrostatics, current electricity, magnetism, optics, and modern physics. Numerical problems carry full derivations so you can see which step you skipped, not just which option was right.
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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: