List of top Physics Questions

For an isothermal expansion of a perfect gas, the value of \( \frac{\Delta P}{P} \) is equal to:
The average translational kinetic energy of \( O_2 \) (molar mass 32) molecules at a particular temperature is 0.048 eV. The translational kinetic energy of \( N_2 \) (molar mass 28) molecules in eV at the same temperature is:
One end of a long metallic wire of length \( L \) tied to the ceiling. The other end is tied with a massless spring of spring constant \( K \). A mass hangs freely from the free end of the spring. The area of cross section and the Young’s modulus of the wire are \( A \) and \( Y \) respectively. If the mass slightly pulled down and released, it will oscillate with a time period \( T \) equal to:
A solid body of constant heat capacity 1 J/°C is being heated by keeping it in contact with reservoirs in two ways:
If the radius of the earth were to shrink by one percent, its mass remaining the same, the value of \( g \) on the earth’s surface would:
An ice block floats in a liquid whose density is less than water. A part of block is outside the liquid. When whole of ice has melted, the liquid level will:
The Young's modulus of a perfectly rigid body is:
A large drop of oil (density 0.8 g/cm³ and viscosity \( \eta_0 \)) floats up through a column of another liquid (density 1.2 g/cm³ and viscosity \( \eta_L \)). Assuming that the two liquids do not mix, the velocity with which the oil drop rises will depend on:
If the unit of force and length be each increased by four times, then the unit of energy is increased by:
Which of the following must be known in order to determine the power output of an automobile?
A man of mass 100 kg is standing on a platform of mass 200 kg, which is kept on a smooth ice surface. If the man starts moving on the platform with a speed 30 m/sec relative to the platform, calculate with what velocity relative to the ice the platform will recoil?
If the force is given by \( F = at + bt^2 \) with \( t \) as time, then the dimensions of \( a \) and \( b \) are:
A projectile can have the same range \( R \) for two angles of projection. If \( t_1 \) and \( t_2 \) are the times of flight in two cases, then what is the product of two times of flight?
What is the moment of inertia of a solid sphere of density \( \rho \) and radius \( R \) about its diameter?
A horizontal overhead powerline is at a height of 4m from the ground and carries a current of 100A from east to west. The magnetic field directly below it on the ground is \( \mu_0 I / 2 \pi r \). What is the magnetic field at this point?
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
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
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 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
The current in a coil varies with time as shown in the figure. The variation of induced emf with time would be
The output wave form of full-wave rectifier is
Calculate the energy released when three \( \alpha \)-particles combined to form a \( \text{C}^{12} \) nucleus, the mass defect is
If a triode value amplification factor is 20 and plate resistance is \( 10 \, \text{k}\Omega \), then its mutual conductance is
In the figure shown, the magnetic field induction as the point \( O \) will be