List of top Physics Questions

A moon completes one revolution around the Earth in $ 27 $ days. If the size (mass) of the moon becomes four times its original size, what will be the new time period?
A source at rest emits sound waves of frequency \( 102 \) Hz. Two observers are moving away from the source of sound in opposite directions each with a speed of \( 10\% \) of the speed of sound. The ratio of the frequencies of sound heard by the observers is?

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

The frequency of fifth harmonic of a closed pipe is equal to the frequency of third harmonic of an open pipe. If the length of the open pipe is 72 cm, then the length of the closed pipe is:
A prism having angle \(\theta\) and refractive index of the material of prism ‘n’ are related by \[ \theta = 2\sin^{-1} \left( \frac{1}{\sqrt{n^2 + 1}} \right) \] - If the angle of minimum deviation is \(60^\circ\), then the angle of the prism is
Two stretched strings A and B when vibrated together produce 4 beats per second. If the tension applied to string A increased, the number of beats produced per second is increased to 7. If the frequency of string B is 480 Hz initially, the frequency of string A is
The path difference between two particles of a sound wave is \( 50 \) cm and the phase difference between them is \( 1.8\pi \). If the speed of sound in air is \( 340 \) m/s, the frequency of the sound wave is?
A polaroid sheet ‘P’ is placed on another similar polaroid sheet ‘Q’ such that the angle between their axes is \(45^\circ\). - The ratio of the intensities of the light emerged from polaroid ‘Q’ and the unpolarised light incident on polaroid ‘P’ is
The speed of a wave on a string is 150 ms\(^{-1}\) when the tension is 120 N. The percentage increase in the tension in order to raise the wave speed by 20\% is
A string of length 25 cm and mass $ 10^{-3} $ kg is clamped at its ends. The tension in the string is 2.5 N. The identical wave pulses are generated at one end and at regular interval of time, $ \Delta t $. The minimum value of $ \Delta t $, so that a constructive interference takes place between successive pulses is:

Explain the construction of a spherical wavefront by using Huygens' principle. 

Four identical thin, square metal sheets, S1, S2, S3 and S4, each of side a are kept parallel to each other with equal distance \(d (≪ a)\) between them, as shown in the figure. Let \(C_0 = \epsilon_0\frac{a^2}{d}, \)where \(\epsilon_0\) is the permittivity of free space.
Alternative_text
Match the quantities mentioned in List-I with their values in List-II and choose the correct option.
List-IList-II
PThe capacitance between S1 and S4, with S2 and S3 not connected, isI \(3C_0\)
QThe capacitance between S1 and S4, with S2 shorted to S3, isII\(\frac{C_0}{2}\)
RThe capacitance between S1 and S3, with S2 shorted to S4, isIII\(\frac{C_0}{3}\)
SThe capacitance between S1 and S2, with S3 shorted to S1, and S2 shorted to S4, isIV\(2\frac{C_0}{3}\)
   \[2C_0\]
Radius of gyration \( K \) of a hollow cylinder of mass \( M \) and radius \( R \) about its long axis of symmetry is:
A thin uniform wire of mass \( m \) and linear mass density \( \rho \) is bent in the form of a circular loop. The moment of inertia of the loop about its diameter is:
The moment of inertia of a solid sphere about its diameter is 20 kg m². The moment of inertia of a thin spherical shell having the same mass and radius about its diameter is:
Three particles of each mass \( m \) are kept at the three vertices of an equilateral triangle of side \( 1 \). The moment of inertia of the system of the particles about any side of the triangle is:
Consider a uniformly dense spherical shell of inner radius \( a \) and outer radius \( b \). If \( M \) is the mass of the shell, the moment of inertia of the spherical shell about an axis passing through its center is:
The maximum range of a projectile is 80 m. If the projectile is projected with the same speed at an angle of \( \frac{\pi}{12} \) with the horizontal, then the range of the projectile is:
A bowling machine placed at a height \( h \) above the earth surface releases different balls with different angles but with the same velocity \( 10 \sqrt{3} \, \text{ms}^{-1} \). All these balls landing velocities make angles 30° or more with horizontal. Then the height \( h \) (in meters) is:

Match the following physical quantities with their respective dimensional formulas.

One second after projection, a projectile is travelling in a direction inclined at \( 45^\circ \) to horizontal. After two more seconds it is travelling horizontally. Then the magnitude of velocity of the projectile is ( \( g = 10 \) ms\(^{-2}\)):
A projectile is given an initial velocity of $(\hat{i} + \hat{j})$ m/s, where $\hat{i}$ is along the ground and $\hat{j}$ is along the vertical direction. The equation of its trajectory is $(g = 10 \, \text{m/s}^2)$.
A projectile is projected with a velocity of \( 20 \, {ms}^{-1} \) at an angle of 45° to the horizontal. After some time its velocity vector makes an angle of 30° to the horizontal. Its speed at this instant (in \( {ms}^{-1} \)) is:
A ball is projected at an angle of \( 45^\circ \) with the horizontal. It passes through a wall of height \( h \) at a horizontal distance \( d_1 \) from the point of projection and strikes the ground at a distance \( d_1 + d_2 \) from the point of projection, then \( h \) is:
An object is projected such that it has to attain maximum range, while another body is projected to reach maximum height. If both objects reached the same maximum height, then find the ratio of their initial velocities.