JEE Main 2025 · 7 Apr 2025 Shift 1

If ε₀ denotes the permittivity of free space and ΦE is the flux of the electric field through the area bounded by the closed surface, then dimensions of (ε₀ dΦE/dt) are that of :

1. Aelectric charge
2. Belectric potential
3. Celectric current
4. Delectric field

Two thin convex lenses of focal lengths 30 cm and 10 cm are placed coaxially, 10 cm apart. The power of this combination is:

1. A1 D
2. B10 D
3. C5 D
4. D20 D

An object of mass 1000 g experiences a time dependent force F⃗ = (2t î + 3t² ĵ) N. The power generated by the force at time t is:

1. A(2t² + 3t³) W
2. B(2t³ + 3t⁵) W
3. C(2t² + 18t³) W
4. D(3t³ + 5t⁵) W

A cubic block of mass m is sliding down on an inclined plane at 60° with an acceleration of g/2, the value of coefficient of kinetic friction is

1. A√3/2
2. B1 − √3/2
3. C√2/3
4. D√3 − 1

Two projectiles are fired from ground with same initial speeds from same point at angles (45° + α) and (45° − α) with horizontal direction. The ratio of their times of flights is

1. A(1 + tan α)/(1 − tan α)
2. B1
3. C(1 + sin 2α)/(1 − sin 2α)
4. D(1 − tan α)/(1 + tan α)

Two wires A and B are made of same material having ratio of lengths Lₐ/Lᵦ = 1/3 and their diameters ratio dₐ/dᵦ = 2. If both the wires are stretched using same force, what would be the ratio of their respective elongations ?

1. A1:3
2. B1:12
3. C1:6
4. D3:4

Two harmonic waves moving in the same direction superimpose to form a wave x = a cos (1.5t) cos (50.5t) where t is in seconds. Find the period with which they beat. (close to nearest integer)

1. A2 s
2. B4 s
3. C6 s
4. D1 s

An ac current is represented as i = 5√2 + 10 cos (650πt + π/6) Amp The r.m.s value of the current is

1. A5√2 Amp
2. B10 Amp
3. C50 Amp
4. D100 Amp