List of top Physics Questions

200 g of water is heated from 40°C to 60°C. The change in its internal energy [No expansion is taken place] specific heat of water is 4200 J kg⁻¹ K⁻¹

An inductor of inductive reactance 80 \(\Omega\) and a resistor of resistance 60 \(\Omega\) are connected in series to an ac source. The impedance and the power factor of the circuit are respectively:

In Young’s double-slit experiment with monochromatic light of wavelength 6000 Å, the fringe width is 3 mm. If the distance between the screen and slits is increased by 50\% and the distance between the slits is decreased by 10\%, then the fringe width is

If \( E_1 = 4V \) and \( E_2 = 12V \), the current in the circuit and potential difference between the points P and Q respectively are:

In a common emitter amplifier, a.c. current gain is 40 and input resistance is 1 kΩ. The load resistance is given as 10 kΩ. Then the voltage gain is:

Force is given by the expression \( F = A \cos(Bx) + C \cos(Dt) \), where 'x' is displacement and 't' is time. The dimensions of \( \frac{D}{B} \) are the same as that of:

A solid flywheel of mass 20 kg and radius 100 mm revolves at 600 revolutions per minute. If the coefficient of friction is 0.1 and to stop the flywheel in 3.14 s, the force to be applied against is approximately:

A cockroach of mass \( m \) is moving with a velocity \( v \) in the anticlockwise direction on the rim of a disc of radius \( R \). The moment of inertia of the disc about the axis is \( I \) and it is rotating in a clockwise direction with an angular velocity \( \omega \). If the cockroach stops moving, the angular velocity of the disc will be:

A uniform rod of length \( 2L \) is placed with one end in contact with the earth and is then inclined at an angle \( \alpha \) to the horizontal and allowed to fall without slipping at the contact point. When it becomes horizontal, its angular velocity will be:

If the angular momentum of an electron in the second orbit of a hydrogen atom is \(J\), then the angular momentum of an electron in the third excited state of hydrogen is:

A piston divides a closed gas cylinder into two parts. Initially, the piston is kept pressed such that one part has pressure P and volume 5V and the other part has pressure 8P and volume V. The piston is now left free. The new pressure if the process is isothermal:

The angle of polarisation for a medium with respect to air is \( 60^\circ \). The critical angle of this medium with respect to air is:

An ideal heat engine operates in Carnot cycle between 127\(^\circ\)C and 27\(^\circ\)C. It absorbs \( 5 \times 10^4 \) cal of heat at higher temperature. Amount of heat converted to work is

Initially the pressure of 1 mole of an ideal gas is \( 10^5 \) Nm\(^2\) and its volume is 16 liters. When it is adiabatically compressed, its final volume is 2 liters. Work done on the gas is (molar specific heat at constant volume \( C_V = \frac{3R}{2} \)):

In the given LCR series circuit the quality factor is

Two spheres A & B of radii 4 cm & 6 cm are given charges of 80 µC & 40 µC respectively. If they are connected by a fine wire, the amount of charge flowing from one to the other is:

A parallel plate capacitor has two square plates of side 5 cm separated by 15 mm. A Pyrex glass slab of dielectric constant \(K = 4.5\) and thickness 10 mm is placed between the plates. The capacitance of the capacitor is:

In the given circuit the currents are \( I_1 = 5A \), \( I_4 = 10A \), and \( I_5 = 15A \). Analyzing the circuit using Kirchhoff’s laws, then \( I_2 \), \( I_3 \), and \( I_6 \) values are:

Path of projectile is given by the equation \( Y = Px - Qx^2 \), match the following accordingly (acceleration due to gravity = \( g \))

A blue lamp emits light of mean wavelength 4500\({Å}\). The lamp is rated at 150 W and 8% efficiency. Then the number of photons are emitted by the lamp per second.

The elastic energy stored per unit volume in terms of longitudinal strain \( e \) and Young’s modulus \( Y \) is:

A body slides down an inclined plane of angle of inclination 30\(^\circ\) with a constant velocity of 10 ms\(^{-1}\). If the body is pushed up the same plane with a velocity of 20 ms\(^{-1}\), the distance moved by the body before coming to rest is (acceleration due to gravity = 10 ms\(^2\))

Match the following (\( f \) is the number of degrees of freedom): \includegraphics[]{100.png}

A force of \( (4\hat{i} + 2\hat{j} + \hat{k}) \) N is acting on a particle of mass \( 2 \) kg displaces the particle from a position of \( (2\hat{i} + 2\hat{j} + \hat{k}) \) m to a position of \( (4\hat{i} + 3\hat{j} + 2\hat{k}) \) m. The work done by the force on the particle in joules is:

Electric field intensity and electric potential at a point due to a point charge are 600 V/m and -3600 V respectively. The distance of the point from the charge and the magnitude of the charge are: