Class 12 - Physics Mock Tests

A wire of resistance R is bent to form a circular loop. The equivalent resistance between the endpoints of a diameter is:

A copper wire has resistance R₀ = 100 Ω at temperature T₀ = 20°C. The temperature coefficient of resistance for copper is α = 0.004/°C. If the wire is heated to T = 120°C, the percentage increase in its resistance is:

In an isothermal process, the internal energy of an ideal gas:

In a common-emitter transistor amplifier, the collector resistance is 2 kΩ and the base resistance is 1 kΩ. If the input signal voltage is 2 V and the current gain β = 100, the output signal voltage is:

A radioactive substance has a half-life of 5 days. The fraction of nuclei remaining after 20 days is:

The magnetic field at the centre of a circular coil of radius R carrying current I is B. If the same wire is rewound into a coil of radius R/2 with the same number of turns and the same current, the new magnetic field at the centre will be:

Two satellites A and B of masses 200 kg and 400 kg orbit the Earth at radii 8000 km and 16000 km respectively. The ratio of their orbital velocities v_A/v_B is:

Light is incident normally on a thin film of thickness t and refractive index μ in air. The reflected light shows a maximum at wavelength λ₁ and a minimum at λ₂ (λ₂ < λ₁), with no other extrema between them. The thickness t is: