List of top Physics Questions

Match List-I with List-II. 

Two point charges are placed on either side of the system, and the electric field is applied with a voltage of 2V. If the electric potential is the same, what will be the interaction between the two charges \( P \) and \( Q \)?
A solenoid having area $ A $ and length $ \ell $ is filled with a material having relative permeability 2. The magnetic energy stored in the solenoid is:
If a coil is connected to an AC circuit, what will be the phase difference between the voltage and current in the circuit?

A cone made of conducting material is given a charge $ Q $. $ \sigma_1, \sigma_2, \sigma_3 $ and $ \sigma_4 $ are charge densities at four points $ P, Q, R $ and $ S $. $ P $ is at the vertex of the cone and $ Q, R, S $ are at the periphery of the base. Choose the correct option.

Pressure of an ideal gas, contained in a closed vessel, is increased by 0.4% when heated by \( 1^\circ \text{C} \). Its initial temperature must be :
A uniform rod of mass 250 g having length 100 cm is balanced on a sharp edge at the 40 cm mark. A mass of 400 g is suspended at the 10 cm mark. To maintain the balance of the rod, the mass to be suspended at the 90 cm mark is:
What is the electric field in the vacuum when the frequency of the radiation is \( 10^{16} \, \text{Hz} \)?
In the diffraction experiment, the angle of diffraction for the first order is \( \theta \). The corresponding wavelength of light is:
A light wave with a frequency of \( 6 \times 10^{14} \, \text{Hz} \) strikes a surface, and the incident power is \( 4 \times 10^{-3} \, \text{W} \). Calculate the energy of each photon.
In a p-n junction diode, when it is forward biased, what happens?

A body of mass $100 \;g$ is moving in a circular path of radius $2\; m$ on a vertical plane as shown in the figure. The velocity of the body at point A is $10 m/s.$ The ratio of its kinetic energies at point B and C is: (Take acceleration due to gravity as $10 m/s^2$)

A body of mass 100 g is moving in a circular
A particle is moving with a constant velocity of \( 5 \, \text{m/s} \) in a circular path of radius \( 2 \, \text{m} \). What is the centripetal acceleration of the particle?
A block of mass \( 5 \, \text{kg} \) is placed on a horizontal surface. The coefficient of friction between the block and the surface is \( 0.4 \). What is the force of friction acting on the block?
A charge of 2 $\mu C$ is placed in an electric field of intensity \( 4 \times 10^3 \, \text{N/C} \). What is the force experienced by the charge?

Which of the following curves possibly represent one-dimensional motion of a particle?

A wire of length $ 25 \, \text{m} $ and cross-sectional area $ 5 \, \text{mm}^2 $ having resistivity $ 2 \times 10^{-6} \, \Omega \cdot \text{m} $ is bent into a complete circle. The resistance between diametrically opposite points will be:
A cube having a side of 10 cm with unknown mass and 200 gm mass were hung at two ends of an uniform rigid rod of 27 cm long. The rod along with masses was placed on a wedge keeping the distance between wedge point and 200 gm weight as 25 cm. Initially the masses were not at balance. A beaker is placed beneath the unknown mass and water is added slowly to it. At given point the masses were in balance and half volume of the unknown mass was inside the water. (Take the density of the unknown mass is more than that of the water, the mass did not absorb water and water density is 1 gm/cm$^3$.) The unknown mass is ______ kg.

A square Lamina OABC of length 10 cm is pivoted at \( O \). Forces act at Lamina as shown in figure. If Lamina remains stationary, then the magnitude of \( F \) is:

A uniform rod of mass 250 g having length 100 cm is balanced on a sharp edge at the 40 cm mark. A mass of 400 g is suspended at the 10 cm mark. To maintain the balance of the rod, the mass to be suspended at the 90 cm mark is:
Displacement of a wave is expressed as $$ x(t) = 5 \cos \left( 628t + \frac{\pi}{2} \right) \, \text{m}. $$ The wavelength of the wave when its velocity is 300 m/s is:
Moment of inertia of a rod of mass \( M \) and length \( L \) about an axis passing through its center and normal to its length is \( \alpha \). Now the rod is cut into two equal parts and these parts are joined symmetrically to form a cross shape. Moment of inertia of cross about an axis passing through its center and normal to the plane containing cross is:

Considering Bohr’s atomic model for hydrogen atom :
(A) the energy of H atom in ground state is same as energy of He+ ion in its first excited state. 
(B) the energy of H atom in ground state is same as that for Li++ ion in its second excited state. 
(C) the energy of H atom in its ground state is same as that of He+ ion for its ground state. 
(D) the energy of He+ ion in its first excited state is same as that for Li++ ion in its ground state.

A particle moves along the x-axis and has its displacement x varying with time t according to the equation \( x = c_0 (t^2 - 2) + c (t - 2)^2 \) where \( c_0 \) and \( c \) are constants of appropriate dimensions. Then, which of the following statements is correct?
For the determination of refractive index of glass slab, a travelling microscope is used whose main scale contains 300 equal divisions equals to 15 cm. The vernier scale attached to the microscope has 25 divisions equals to 24 divisions of main scale. The least count (LC) of the travelling microscope is (in cm):