List of top Physics Questions

Ice starts freezing in a lake with water at 0°C when the atmospheric temperature is –10°C. If the time taken for 1 cm of ice to be formed is 12 min, the time taken for the thickness of the ice to change from 1 to 2 cm will be
A train of 150 m length is going towards north direction at a speed of 10 m/s. A parrot flies at a speed of 5 m/s towards south direction parallel to the railway track. The time taken by the parrot to cross the train is equal to
The ratio of the speed of an object to the speed of its real image of magnification \(m\) of a convex mirror is
The wavelength of the \(K_\alpha\) line for an element of atomic number 43 is \(\lambda\). Then the wavelength of the \(K_\alpha\) line for an element of atomic number 29 is
In the Boolean Algebra \(\overline{A \cdot B}\) is same as
An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The Coulomb force F between the two is
For a particle executing simple harmonic motion, the kinetic energy \(k\) is given by \(k = k_0 \cos^2 \omega t\). The maximum value of potential energy is
A charge q is located at the centre of a cube. The electric flux through any face is
When a force \(F_1\) acts on a particle, frequency is 6 Hz and when a force \(F_2\) acts, frequency is 8 Hz. What is the frequency when both the forces act simultaneously in same direction?
A simple pendulum has time period \(T_1\). The point of suspension is now moved upward according to the relation \(y = kt^2\) where \(k = 1\) ms\(^{-2}\). The time period now becomes \(T_2\). The ratio \(\frac{T_1^2}{T_2^2}\) is \((g = 10\) m/s\(^2)\)
The energy supplied to Kolkata by the state electricity board during an average November week day was 40 GWh. If this energy could be obtained by the conservation of matter, how much mass would have to be annihilated?
An observer looks at a tree of height 15 m with a telescope of magnifying power 10. To him the tree appears
An inductor is connected to a battery through a switch. Induced emf is \(e_1\) when the switch is pressed and \(e_2\) when the switch is opened. Then
Two weights \(w_1\) and \(w_2\) are suspended to the two strings on a frictionless pulley. When the pulley is pulled up with an acceleration \(g\) then the tension in the string is
The speed of a wave on a string is 150 m/s when the tension is 120 N. The percentage increase in the tension in order to raise the wave speed by 20% is
If the work function of a metal is 6.875 eV, its threshold wavelength will be (Take \(c = 3 \times 10^8\) m/s)
The temperature of the black body increases from \(T\) to \(2T\). The factor by which the rate of emission will increase is
If the energy of a hydrogen atom in \(n^{\text{th}}\) orbit is \(E_n\) then energy in the \(n^{\text{th}}\) orbit of a singly ionized helium atom will be
If the length of a pendulum is made 9 times and mass of bob is made 4 times, then the value of time period becomes
Which of the following is unipolar transistor?
A police jeep is chasing with velocity of 45 km/h a thief in another jeep moving with velocity 153 km/h. Police fires a bullet with muzzle velocity of 180 m/s. The velocity with which it will strike the car of the thief is
Two spheres of equal masses, one of which is a thin spherical shell and the other a solid, have the same moment of inertia about their respective diameters. The ratio of their radii will be
A man crosses a 320 m wide river perpendicular to the current in 4 min. If in still water he can swim with a speed 5/3 times that of the current, then the speed of the current, in m/min is
The correct relation between \(\alpha\) and \(\beta\) in a transistor is
The rate of flow of glycerine of density \(1.25 \times 10^3\) kg m\(^{-3}\) through the conical section of a pipe if the radii of its ends are 0.1 m and 0.04 m and the pressure drop across its length 10 N m\(^{-2}\) is