List of top Physics Questions

A known positive charge is located at point P as shown above, between two unknown charges, Q1 and Q2. P is closer to Q2 than Q1. If the net electric force acting on the charge at P is zero, it may correctly be concluded that:
A square closed loop of area A, lying in the horizontal plane, is moving horizontally with velocity \( v \) in a uniform vertical magnetic field \( B \). Which one of the following statements is FALSE?
Helium is two times heavier than H2. The average kinetic energy per molecule for helium at 300K is
If the initial decay rate of a radioactive sample is \( R_0 \), then the decay rate after a half-life time \( T_{1/2} \) is
If the distance between an object and its two times magnified virtual image produced by a curved mirror is 15 cm, the focal length of the mirror must be:
In YDSE, monochromatic light falls on a screen 1.80 m from two slits separated by 2.08 mm. The first and second order bright fringes are separated by 0.553 mm. The wavelength of light used is:
A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit will be:
Two positive point charges are separated by a distance of 4 m in air. If the sum of the two charges is \( 36 \mu C \) and the electrostatic force between them is \( 0.18 \) N, then the bigger charge is:
The property of light which cannot be explained by Huygen's construction of a wavefront is:
When a light ray incidents on the surface of a medium, the reflected ray is completely polarized. Then the angle between reflected and refracted rays is:
Which figure shows the correct variation of applied potential difference (\(V\)) with photoelectric current (\(I\)) at two different intensities of light (\(I_1<I_2\)) of same wavelengths:

If the kinetic energy of a free electron doubles, its de-Broglie wavelength changes by the factor: 
 

Two identical conducting spheres P and S with charge Q on each, repel each other with a force 16N. A third identical uncharged conducting sphere R is successively brought in contact with the two spheres. The new force of repulsion between P and S is :
The densities of the nuclei: \(^{24}_{12}Mg\), \(^{40}_{20}Ca\) and \(^{88}_{38}Sr\),
In the following circuit, the charge stored in capacitors \( C_1 \), \( C_2 \), and \( C_3 \) are
For a system executing simple harmonic motion,
The magnetic properties of magnets are
Consider the following spring configurations:
If the first spring is stretched by an amount \( \Delta x \), the second system will be stretched by:
Which of the following is not a representation of uniform motion?
Consider a uniformly dense spherical shell of inner radius \( a \) and outer radius \( b \). If \( M \) is the mass of the shell, the moment of inertia of the spherical shell about an axis passing through its center is:
Diffraction of light involves
In the circuit below, A and B represent two inputs and C represents the output. The circuit represents:
The current I drawn from the 5 volt source will be:
If the angular momentum of a planet of mass \(M\), moving around the sun in a circular orbit, is \(L\). The areal velocity of the planet about the center of the sun is
The torque of a force \( \mathbf{F} = 4\hat{i} - 2\hat{j} + 3\hat{k} \) about the origin is \( \mathbf{r} \). The force acts on a particle having position vector \( \hat{i} + 2\hat{j} - \hat{k} \). Then the torque \( \mathbf{r} \) is: