List of top Physics Questions

The work function of a metal is 2 eV. What is the threshold frequency for the photoelectric emission? (Take Planck's constant $ h = 6.63 \times 10^{-34} \, \text{Js} $, $ 1 \, \text{eV} = 1.6 \times 10^{-19} \, \text{J} $)
Two resistors, 4 $\Omega$ and 6 $\Omega$, are connected in parallel to a 12 V battery. What is the total current drawn from the battery?
A block of mass 5 kg is placed on a frictionless incline of angle $30^\circ$. What is the acceleration of the block down the incline? (Take $g = 9.8\, m/s^2$)
In a series combination of capacitors connected across a battery
An object of mass $ 0.5 \, \text{kg} $ is moving with a velocity of $ 10 \, \text{m/s} $. What is the momentum of the object?
A hemispherical vessel is completely filled with a liquid of refractive index \( \mu \). A small coin is kept at the lowest point \( O \) of the vessel as shown in the figure. The minimum value of the refractive index of the liquid so that a person can see the coin from point \( E \) (at the level of the vessel) is:
A hemispherical vessel is completely filled with a liquid of refractive index
A simple pendulum has a time period of 2 s on Earth's surface. What is its time period at a height equal to the Earth's radius (R)? (Acceleration due to gravity at height h is \( g_h = \frac{g}{(1 + h/R)^2} \)).
A galvanometer having a coil of resistance 30 \( \Omega \) needs 20 mA of current for full-scale deflection. If a maximum current of 3 A is to be measured using this galvanometer, the resistance of the shunt to be added to the galvanometer should be \( X \, \Omega \), where \( X \) is:
The electric field E associated with a progressive electromagnetic wave is given by E = E\(_0\)sin(kx - \(\omega\)t). If B\(_0\) is the amplitude of the magnetic field associated with the wave, then
A 12 V battery connected to a 6 \(\Omega\), 10 mH coil through a switch drives a constant current in the circuit. The switch is suddenly opened. Assuming that it took 1 ms to open the switch, the average emf induced across the coil would be
A battery of emf 12 V and internal resistance 3 \(\Omega\) is connected to an external resistor. If the current in the circuit is 0.6 A, the voltage across the external resistor will be
A bulb rated 60 W operates for 2 hours. How much energy does it consume in this time?
Two like charges are placed 1 m apart in air. If the force between them is 9 N, and one charge is 1 C, what is the other charge? (Use $ k = 9 \times 10^9 \, \text{Nm}^2/\text{C}^2 $)
Two infinitely long straight wires ‘1’ and ‘2’ are placed \(d\) distance apart, parallel to each other, as shown in the figure. They are uniformly charged having charge densities \(\lambda\) and \(-\frac{\lambda}{2}\) respectively. Locate the position of the point from wire ‘1’ at which the net electric field is zero and identify the region in which it lies.
Two infinitely long straight wires ‘1’ and ‘2’ are placed d distance apart,
Two concave refracting surfaces of equal radii of curvature and refractive index 1.5 face each other in air as shown in figure. A point object O is placed midway, between P and B. The separation between the images of O, formed by each refracting surface is:
Two concave refracting surfaces of equal radii of curvature and refractive index
The electric field at a point on the axis of a uniformly charged ring of radius R at a distance x from its center is given by: \[ E = \frac{1}{4\pi\epsilon_0} \cdot \frac{2\pi kQx}{(x^2 + R^2)^{3/2}}. \] If x = 2R, what is the magnitude of the electric field?

The output voltage in the following circuit is (Consider ideal diode case): 

A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The temperature of the wire is 1727°C and power radiated by the wire is 94.2 W. Its emissivity is $ \frac{x}{8} $, where $ x = \ldots $

Which of the following circuits has the same output as that of the given circuit?

A 10 $\mu\text{C}$ charge is placed in an electric field of $ 5 \times 10^3 \text{N/C} $. What is the force experienced by the charge?

A wire of length 2 m and resistance 8 \(\Omega\) is stretched to double its original length, keeping the volume constant. What is the new resistance of the wire?
A circular coil of area \(3 \times 10^{-2} \text{ m}^2\), 900 turns and a resistance of 1.8 Ω is placed with its plane perpendicular to a uniform magnetic field of \(3.5 \times 10^{-5}\) T. The current induced in the coil when it is rotated through 180° in half a second is
A bullet of mass $m$ moving with a velocity $u$ gets embedded in a block of mass $M$ initially at rest. If $\mu$ is the coefficient of friction between the block and the ground, then the displacement of the block due to the impact is:
A uniform circular disc of mass $\dfrac{\pi}{40}$ kg is rotating about an axis passing through its center and perpendicular to its plane with an angular speed of 150 rev/min. If the angular momentum of the disc is 6.25 Js, then its radius is:
To increase the length of a metal rod by 0.4%, the temperature of the rod is to be increased by (Coefficient of linear expansion of the metal = \(20 \times 10^{-6}\) °C⁻¹)