List of top Physics Questions

The wavelength $\lambda_e$ of an electron and $\lambda_P$ of a photon of same energy E are related by:

When a proton is released from rest in a room, it starts with an initial acceleration $a_0$ towards west. When it is projected towards north with a speed $v_0$ it moves with an initial acceleration $3a_0$ towards west. The electric and magnetic fields in the room are:

Infinite number of bodies, each of mass 2 kg are situated on x-axis at distance 1m, 2m, 4m, 8m, ...., respectively, from the origin. The resulting gravitational potential due to this system at the origin will be

An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass $1\, kg$ moves with a speed of $12 \, ms^{-1}$ and the second part of mass $2 \,kg$ moves with $8 \, ms^{-1}$ speed. If the third part files off with $4 \, ms^{-1}$ speed, then its mass is :

The heart is pumping blood at x kg per unit time, with a constant velocity v. The force required is

The transverse displacement of a string fixed at both ends is given by $y=0.6 \sin \left(\frac{2 \pi x}{3}\right) \cos (120 \pi t)$ where $x$ and $y$ are in metres and $t$ is in seconds. The length of the string is $1.5\, m$ and its mass is $3.0 \times 10^{-2} kg$. The tension in the string is equal to

A galvanometer of resistance \( G \) is shunted by a resistance \( S \, \Omega \). To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is

Three charges, each \( +q \), are placed at the corners of an isosceles triangle ABC of sides BC and AC, 2a. D and E are the mid-points of BC and CA. The work done in taking a charge \( Q \) from D to E is

A transistor is operated in common emitter configuration at \( V_C = 2V \) such that a change in the base current from 100 μA to 300 μA produces a change in the collector current from 10 mA to 20 mA. The current gain is

A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron

Charge \( q \) is uniformly spread on a thin ring of radius \( R \). The ring rotates about its axis with a uniform frequency \( f \). The magnitude of magnetic induction at the centre of the ring is

If a triode value amplification factor is 20 and plate resistance is \( 10 \, \text{k}\Omega \), then its mutual conductance is

The current in a coil varies with time as shown in the figure. The variation of induced emf with time would be

Calculate the energy released when three \( \alpha \)-particles combined to form a \( \text{C}^{12} \) nucleus, the mass defect is

The output wave form of full-wave rectifier is

In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is

In photoelectric emission, the current varies with time as shown. The variation of induced emf with time would be

In the figure shown, the magnetic field induction as the point \( O \) will be

Each resistance shown in figure is \( 2 \, \Omega \). The equivalent resistance between A and B is

The turn ratio of transformers is given as 2:3. If the current through the primary coil is 3A, thus calculate the current through load resistance.

In an AC circuit, the potential across an inductance and resistance joined in series are respectively 16V and 20V. The total potential difference across the circuit is

Highly energetic electrons are bombarded on a target of an element containing 30 neutrons. The ratio of radius of nucleus to that of Helium nucleus is (14)³. The atomic number of nucleus will be

If hydrogen atom is its ground state absorbs \( 10.2 \, \text{eV} \) of energy. The orbital angular momentum increases by

In hydrogen atom, an electron is revolving in the orbit of radius 0.53 Å with \( 6.6 \times 10^{15} \) radiations. Magnetic field produced at the centre of the orbit is

The dipole moment of the short bar magnet is \( 12.5 \, \text{A} \cdot \text{m}^2 \). The magnetic field on its axis at a distance of \( 0.5 \, \text{m} \) from the centre of the magnet is