Physics questions for JEE Main

In an experiment the values of two spring constants were measured as k₁ = (10 ± 0.2) N/m and k₂ = (20 ± 0.3) N/m. If these springs are connected in parallel, then the percentage error in equivalent spring constant is:

10 mole of oxygen is heated at constant volume from 30 °C to 40 °C. The change in the internal energy of the gas is ______ cal. (The molecular specific heat of oxygen at constant pressure, Cₚ = 7 cal/mol °C and R = 2 cal/mol °C.)

An electromagnetic wave of frequency 100 MHz propagates through a medium of conductivity σ = 10 mho/m. The ratio of maximum conducting current density to maximum displacement current density is ______. [Take 1/(4πε₀) = 9 × 10⁹ N m²/C²]

A simple pendulum has a bob with mass m and charge q. The pendulum string has negligible mass. When a uniform and horizontal electric field E is applied, the tension in the string changes. The final tension in the string, when pendulum attains an equilibrium position is ______. (g: acceleration due to gravity)

Given below are two statements: Statement I: A satellite is moving around earth in the orbit very close to the earth surface. The time period of revolution of satellite depends upon the density of earth. Statement II: The time period of revolution of the satellite is T = 2π√(Rₑ/g) (for satellite very close to the earth surface), where Rₑ radius of earth and g acceleration due to gravity. In the light of the above statements, choose the correct answer from the options given below:

The strain–stress plot (strain on the y-axis, stress on the x-axis) for materials A, B, C and D are straight lines through the origin with slopes in the order A > B > D > C. Which material has the largest Young's modulus?

The exit surface of a prism with refractive index n is coated with a material having refractive index n/2. When this prism is set for minimum angle of deviation it exactly meets the condition of critical angle. The prism angle is:

A regular hexagon is formed by six wires each of resistance r Ω and the corners are joined to centre by wires of same resistance. If the current enters at one corner and leaves at the opposite corner, the equivalent resistance of the hexagon between the two opposite corners will be: