List of top Physics Questions

A voltmeter of resistance $400 \, \Omega$ is used to measure the emf of a cell with an internal resistance of $4 \, \Omega$. The error in the measurement of emf of the cell is:

Two capacitors of capacitances $ 1\mu F $ and $ 2\mu F $ can separately withstand potentials of $ 6 $ kV and $ 4 $ kV respectively. The total potential, they together can withstand when they are connected in series is:

A constant force of \[ \mathbf{F} = (8\hat{i} - 2\hat{j} + 6\hat{k}) \text{ N} \] acts on a body of mass 2 kg, displacing it from \[ \mathbf{r_1} = (2\hat{i} + 3\hat{j} - 4\hat{k}) \text{ m to } \mathbf{r_2} = (4\hat{i} - 3\hat{j} + 6\hat{k}) \text{ m}. \] The work done in the process is:

Wave picture of light has failed to explain
(1) photoelectric effect
(2) interference of light
(3) diffraction of light
(4) polarization of light

A metal block of mass 120 g is heated to a temperature of 100$^\circ$C and placed on a huge block of ice at 0$^\circ$C. The specific heat capacity of the metal is 0.12 cal/$^\circ$C and the latent heat of fusion of ice is 80 cal/g. The mass of the ice melted is:

The operation of a nuclear reactor is said to be critical when the value of neutron multiplication factor $ K $ is

The temperature at which the rms speed of oxygen molecules is 75\% of the rms speed of nitrogen molecules at a temperature of $ 287^\circ C $ is:

If the excess pressures inside two soap bubbles are in the ratio $ 2:3 $, then the ratio of the volumes of the soap bubbles is:

The total internal energy of 4 moles of a diatomic gas at a temperature of $27^\circ C$ is: (Universal gas constant $ R = 8.31 \, \text{J mol}^{-1} \text{K}^{-1} $)

A body is thrown vertically upwards with a velocity of 35 ms−1 from the ground.The ratio of the speeds of the body at times 3 s and 4 s of its motion is:

An incompressible fluid is flowing through a tube of uniform cross-section. The increase in the power of the pump required to double the rate of flow is:

A body moving with uniform acceleration travels a distance of 25 m in the fourth second and 37 m in the sixth second. The distance covered by the body in the next two seconds is

The power gain of a transistor operating in common emitter configuration is 32,000. If the input and output resistances of the circuit are 1200 $ \Omega $ and 6000 $ \Omega $ respectively, then the current gain is:

In a time ‘’t", the amplitude of vibrations of a damped oscillator becomes half of its initial value, then the mechanical energy of the oscillator decreases by:

Regarding fundamental forces in nature, the correct statement is

Two particles of charges in the ratio $ 1:2 $ and masses in the ratio $ 2:3 $ moving along a straight line enter a uniform magnetic field at right angles to the direction of the field. If the radii of the circular paths of the particles in the magnetic field are in the ratio $ 3:4 $, then the ratio of the initial linear momenta of the two particles is:

If the relaxation time is doubled and the applied electric field is tripled, then the drift speed of electrons:

If $ dQ, dU, dW $ are heat energy absorbed, change in internal energy, and external work done respectively by a diatomic gas at constant pressure, then $ dW : dU : dQ $ is:

A block of mass 0.5 kg is at rest on a horizontal table. The coefficient of kinetic friction between the table and the block is 0.2. If a horizontal force of 5 N is applied on the block, the kinetic energy of the block in a time of 4 s is (Acceleration due to gravity = 10 m/s$^2$)

The electric flux due to an electric field \[ \vec{E} = (8\hat{i} + 13\hat{j}) \text{ NC}^{-1} \] through an area 3 m$^2$ lying in the XZ plane is:

A big liquid drop splits into 'n' similar small drops under isothermal conditions, then in this process:

Match List I with List II.

List I (Spectral Lines of Hydrogen for transitions from)		List II (Wavelength (nm))
A.	n₂ = 3 to n₁ = 2	I.	410.2
B.	n₂ = 4 to n₁ = 2	II.	434.1
C.	n₂ = 5 to n₁ = 2	III.	656.3
D.	n₂ = 6 to n₁ = 2	IV.	486.1

Choose the correct answer from the options given below:

An element consists of a mixture of three isotopes A, B, and C of masses $ m_1 $, $ m_2 $, and $ m_3 $ respectively. If the relative abundances of the three isotopes A, B, and C is in the ratio 2:3:5, the average mass of the element is:

The half-life of a radioactive substance is 12 minutes. The time gap between 28\% decay and 82\% decay of the radioactive substance is:

At room temperature, gaseous hydrogen is bombarded with a beam of electrons of 13.6 eV energy. The series to which the emitted spectral line belongs to: