List of top Physics Questions

A bicycle tire is filled with air at a pressure of $ 270 $ kPa at $ 27^\circ C $. What is the approximate pressure of the air in the tire when the temperature increases to $ 36^\circ C $?

The work done in placing a charge of $ 8 \times 10^{-18} $ coulomb on a capacitor of capacitance 100 microfarad is:

The effect of an increase in temperature on the number of electrons in the conduction band ($ n_e $) and the resistance of a semiconductor will be as follows:

The resistance of a wire is $ 5 \Omega $. What will be its new resistance in ohms if stretched to 5 times its original length?

A particle of mass $ m $ moving with velocity $ v $ collides with a stationary particle of mass $ 2m $. After the collision, they stick together and continue to move with velocity:

The free space inside a current carrying toroid is filled with a material of susceptibility $ \chi = 2 \times 10^{-2} $. The percentage increase in the value of magnetic field inside the toroid will be:

Two planets $ A $ and $ B $ have radii $ R $ and $ 1.5R $, and densities $ \rho $ and $ \frac{\rho}{2} $ respectively. The ratio of acceleration due to gravity at the surface of $ B $ to $ A $ is:

Why did the time period of rotation of Earth decrease by microseconds after the Japan 2011 earthquake?

In a reflecting telescope, a secondary mirror is used to:

Which of the following Maxwell's equations is valid for time varying conditions but not valid for static conditions:

The ratio of the speed of sound in hydrogen gas to the speed of sound in oxygen gas at the same temperature is:

A charged particle is moving in a uniform magnetic field $ \mathbf{B} = 2\hat{i} + 3\hat{j} $ T. If it has an acceleration of $ \mathbf{a} = \alpha\hat{i} - 4\hat{j} $ m/s², then the value of $ \alpha $ will be:

In a current carrying coil of inductance 60 mH,the current is changed from 2.5 A in one direction to 2.5 A in the opposite direction in 0.10 sec. The average induced EMF in the coil will be:

At a certain depth "$d$" below surface of earth, value of acceleration due to gravity becomes four times that of its value at a height $3 R$ above earth surface Where $R$ is Radius of earth (Take $R =6400\, km$ ) The depth $d$ is equal to

A parallel plate capacitor consists of two square metal plates 5.0 cm of side and separated by 1 cm. A sulphur slab of thickness 5 mm is placed on the lower plate. What will be the capacitance of the capacitor? (Dielectric constant of sulphur = 4)

A sinusoidal voltage of amplitude 25 V and frequency 50 Hz is applied to a half-wave rectifier using a P-N junction diode. No filter is used, and the load resistor is $ 1000\Omega $. The forward resistance $ R_f $ of the ideal diode is $ 10\Omega $. The percentage rectifier efficiency is:

Two identical blocks A and B, each of mass 'm' resting on a smooth floor are connected by a light spring of natural length L and spring constant K, with the spring at its natural length. A third identical block 'C' (mass m) moving with a speed v along the line joining A and B collides with A. the maximum compression in the spring is

The half-life of radioactive radon is 3.8 days. The time at the end of which $\frac{1}{20}th$ of the Radon sample will remain undecayed is (given log₁₀^e=0.4343)

In a Rutherford scattering experiment, when a projectile of charge $ Z_1 $ and mass $ M_1 $ approaches a target nucleus of charge $ Z_2 $ and mass $ M_2 $, the distance of closest approach is $ r_0 $. The energy of the projectile is:

An electron (mass = $ 9 \times 10^{-31} $ kg, charge = $ 1.6 \times 10^{-19} $ C) moving with a velocity of $ 10^6 $ m/s enters a magnetic field. If it describes a circle of radius $ 0.1 $ m, then the strength of the magnetic field must be:

A square frame of side $ 10 $ cm and a long straight wire carrying current $ 1A $ are in the plane of the paper. Starting from close to the wire, the frame moves towards the right with a constant speed of $ 10 $ m/s (see figure). The induced EMF at the time the left arm of the frame is at $ x = 10 $ cm from the wire is:

In YDSE, how many maximas can be obtained on a screen, including central maxima, on both sides of the central fringe if $ \lambda = 3000$ Å, $ d = 5000$ Å?

The force between two short bar magnets with magnetic moments $ M_1 $ and $ M_2 $ whose centers are $ r $ meters apart is 8 N when their axes are in the same line. If the separation is increased to $ 2r $, the force between them is reduced to:

A force $ \mathbf{F} = \alpha \hat{i} + 3 \hat{j} + 6 \hat{k} $ is acting at a point $ \mathbf{r} = 2 \hat{i} - 6 \hat{j} - 12 \hat{k} $. The value of $ \alpha $ for which angular momentum about the origin is conserved is:

A parallel plate air capacitor of capacitance $ C $ is connected to a cell of emf $ V $ and then disconnected from it. A dielectric slab of dielectric constant $ K $, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?