List of top Physics Questions

To what depth must a rubber ball be taken in deep sea so that its volume is decreased by $0.1 \%$. (Take, density of sea water =$10^{3} \, kg$ $m^{-3}$, bulk modulus of rubber =$9\times10^{8}N$ $m^{-2}$, $g=10 \,m$ $s^{-2})$

To shield an instrument from an external magnetic field it may be placed in a cabinet made of :

To shield an instrument from external magnetic field, it is placed inside a cabin made from

To maintain a rotor at a uniform angular speed of $200\,rad\,s^{-1}$ an engine needs to transmit a torque of $180\,Nm$. The power of the engine required is (Assume the efficiency of the engine as 100%).

To find the distance $d$ over which a signal can be seen clearly in foggy conditions, a railways engineer uses dimensional analysis and assumes that the distance depends on the mass density $\rho$ of the fog, intensity (power/area) $S$ of the light from the signal and its frequency $v$. The engineer finds that $d$ is proportional to $S^{1/n}$. The value of $n$ is

To get three images of a single object, one should have two plane mirrors at an angle of

To correct myopia, the focal length of the concave lens should be:

Time period of SHM is given by T = 2$\pi$ [displacement / acceleration]$^{1/2}$. When displacement increases, the time period

Time period of oscillation of a spring is $12\, s$ on earth. What shall be the time period if it is taken to moon?

Threshold wavelength depends upon:

Three waves of equal frequency having amplitudes 10mm, 4mm and 7mm arrive at a given point with successive phase difference $\pi/2$ . The amplitude of the resulting wave in mm is given by

Three vessels $A$, $B$ and $C$ of different shapes contain a water upto the same height as shown in the figure. $P_{A}$, $P_{B}$ and $P_{c}$ be the pressures exerted by the water at the bottom of the vessels $A$, $B$ and $C$ respectively Then

Three uniform spheres of mass M and radius R earth are kept in such a way that each touches the other two. The magnitude of the gravitational force on any of the spheres due to the other two is

Three particles of masses 1 kg, 2 kg and 3 kg are situated at the corners of an equilateral triangle of side $b$. The coordinates of the centre of mass are

Three particles of masses $1\, kg, \frac{3}{2} kg$, and $2\,kg$ are located at the vertices of an equilateral triangle of side $a$. The $x, y$ coordinates of the centre of mass are

Three masses each of mass $m$ are placed at the vertices of an equilateral triangle $ABC$ of side $l$ as shown in figure. The force acting on a mass $2m$ placed at the centroid $O$ of the triangle is

Three identical bar magnets each of magnetic moment M are arranged in the form of an equilateral triangle such that at two vertices like poles are in contact. The resultant magnetic moment will be

Three charges of equal magnitude $q$ is placed at the vertices of an equilateral triangle of side $l$. The force on a charge $Q$ placed at the centroid of the triangle is

Three containers of the same volume contain three different gases. The masses of the molecules are $m_1, m_2$ and $m_3$ and the number of molecules in their respective containers are $N_1, N_2$ and $N_3$. The gas pressure in the containers are $P_1, P_2$ and $P_3$ respectively. All the gases are now mixed and put in one of these containers. The pressure P of the mixture will be

Three equal masses of 1 kg each are placed at the vertices of an equilateral triangle PQR and a mass of 2 kg is placed at the centroid O of the triangle which is at a distance of $\sqrt2$ m from each of the vertices of the triangle. The force, in newton, acting on the mass of 2 kg is

Three charges each equal to $+2 \,C$ are placed at the corners of an equilateral triangle. If the force between any two charges be $F$, then the net force on either will be :

Three capacitors of capacitances $3\,\mu F$,$9\,\mu F$ and $18\,\mu F$ are connected once in series and another time in parallels. The ratio of equivalent capacitances in the two cases $(C_s/C_p)$ will be

Three charge q, Q and 4q are placed in a straight line of length l at points distant 0, $\frac{1}{2}$ and l respectively from one end. In order to make the net froce on q zero, the charge Q must be equal to

Though quantum theory of light can explain a number of phenomena observed with light, it is necessary to retain the wave-nature of light to explain the phenomena of:

There is some change in length when a 33000 N tensile force is applied on a steel rod of area of cross-section $10^{-3}m^2$. The change of temperature required to produce the same elongation of the steel rod when heated is $(Y=3\times 10^{-11} \,N/m^2 , \alpha = 1.1 \times 10^{-5} /^0C )$