List of top Physics Questions

The electric flux from a cube of side 1 m is \(\Phi\). When the side of the cube is made 3 m and the charge enclosed by the cube is made one-third of the original value, then the flux from the bigger cube will be:
A lens of power \( +1 \, \text{D} \) is made in contact with another lens of power \( -2 \, \text{D} \). The combination will then act as:
A particle at rest decays into two particles of mass \( m_1 \) and \( m_2 \) and move with velocities \( v_1 \) and \( v_2 \). The ratio of their de Broglie wave lengths \( \lambda_1 : \lambda_2 \) is:
An uniform sphere of mass \( M \) and radius \( R \) exerts a force of \( F \) on a small mass \( m \) placed at a distance of \( 3R \) from the centre of the sphere. A spherical portion of diameter \( R \) is cut from the sphere as shown in the fig. The force of attraction between the remaining part of the disc and the mass \( m \) is:
If the ratio of specific heat of a gas at constant pressure to that at constant volume is \( \gamma \), the change in internal energy of a mass of a gas when the volume changes from \( V \) to 3\( V \) at constant pressure is:
A magnetic field does not interact with:
A magnetic field does not interact with:
If reaction is \(R\) and coefficient of friction is \(\mu\), what is the work done against friction in moving a body by distance \(d\)?
PQRS is square of side 1 m. A charge of \(100 \, \mu C\) is placed at the centre of the square. Then the work done to take \(3 \, \mu C\) charge from the corner P to the corner R.
When the angle of incidence on one face of the equilateral glass prism is \(\frac{3}{4}\) of the angle of the prism, the ray of light undergoes minimum deviation. If the velocity of light in vacuum is \(c\), then the velocity of light in the glass is:
Two point charges \( 20 \, \mu C \) and \( -10 \, \mu C \) are separated by a distance of 1 m in air. At what point on the line joining the two charges, the electric potential is zero.
In an adiabatic expansion of air, the volume is increased by 6.2%. The percentage change in pressure is (\( \gamma = 1.4 \))

In the figure, first the capacitors are fully charged by closing the key K. Then after opening the Key, a dielectric material with dielectric constant \( \kappa = 2 \) is filled in the space between the plates of both the capacitors. At this state the ratio of the charge on the capacitor \(C_1\) to that of \(C_2\) is:

A spherical metal ball of density \( \rho \) and radius \( r \) is immersed in a liquid of density \( \sigma \). When an electric field is applied in the upward direction the metal ball remains just suspended in the liqui(D) Then the expression for the charge on the metal ball is:
The energy gap between valence band and the conduction band for a given material is 6 eV. What would be the energy associated with the second excited state of Li?
Water from a tap of cross-sectional area \(1 \, \text{cm}^2\), falls vertically downwards at \(2 \, \text{m/s}\). The cross-sectional area of the stream, 20 cm below the tap is (assume that pressure is constant throughout and the flow is streamlined; \(g = 10 \, \text{m/s}^2\)).
In a nuclear reaction, 2 deuteron nuclei combine to form a helium nucleus. The energy released in MeV will be: (Given mass of deuteron = 2.01355 amu and mass of helium nucleus = 4.0028 amu.)
The mass number of two nuclei P and Q are 27 and 125 respectively. The ratio of their radii \( R_P : R_Q \) is given by:
A man grows into a giant such that his height increases to 8 times his original height. Assuming that his density remains the same, the stress in the leg will change by a factor of
The current sensitivity of a galvanometer having 20 divisions is \( 10 \mu A / \text{div} \). If the resistance of the galvanometer is 100Ω, then the value of the resistance to be used to convert this galvanometer into a voltmeter to read up to 1 V is:
A closed container constrains a homogeneous mixture made of, 2 moles of an ideal monatomic gas(\(\gamma=\frac{5}{3}\)) and one mole of an ideal diatomic gas(\(\gamma=\frac{7}{5}\)). Here, γ is the ratio of the specific heat at content pressure and constant volume of an ideal gas. The gas mixture does a work of 66 joules when heated at constant pressure. The change in its internal energy is ____Joule.
A plane-polarized blue light ray is incident on a prism such that there is no reflection from the surface of the prism. The angle of deviation of the emergent ray is 𝛿 = 60° (see Figure-1). The angle of minimum deviation for red light from the same prism is 𝛿min = 30° (see Figure-2). The refractive index of the prism material for blue light is √3. Which of the following statement(s) is(are) correct?
A plane-polarized blue light ray

A series LCR circuit is connected to a 45 sin(𝜔𝑡) Volt source. The resonant angular frequency of the circuit is \(10^5\) rad s−1 and current amplitude at resonance is I0. 

When the angular frequency of the source is 𝜔 =\(8 ×\) \(10^4\) rad s−1, the current amplitude in the circuit is 0.05 I0. If L=50 mH, match each entry in List-I with an appropriate value from List-II and choose the correct option. 

List-I List-II 
(P) I0 in mA (1)  44.4
(Q) The quality factor of the circuit(2) 18 
(R) The bandwidth of the circuit in rad s−1(3) 400
(S) The peak power dissipated at resonance in Watt(4) 2250 
 (4) 2250

Match the temperature of a black body given in List-I with an appropriate statement in List-II, and choose the correct option.
[Given: Wien’s constant as \(2.9 \times 10^{−3} m^{-K}\) and \(\frac{hc}{e} = 1.24 \times 10^{−6} V^{-m}\)]

List-IList-II
(P)2000 K(1)The radiation at peak wavelength can lead to emission of photoelectrons from a metal of work function 4 eV.
(Q)3000 K(2)The radiation at peak wavelength is visible to human eye.
(R)5000 K(3)The radiation at peak emission wavelength will result in the widest central maximum of a single slit diffraction.
(S)10000 K(4)The power emitted per unit area is \(\frac{1}{16}\) of that emitted by a blackbody at temperature 6000 K.
  (5)The radiation at peak emission wavelength can be used to image human bones.

A container has a base of 50 cm × 5 cm and height 50 cm, as shown in the figure. It has two parallel electrically conducting walls each of area 50 cm × 50 cm. The remaining walls of the container are thin and non-conducting. The container is being filled with a liquid of dielectric constant 3 at a uniform rate of 250 cm3s−1. What is the value of the capacitance of the container after 10 seconds? [Given: Permittivity of free space 𝜖0 = 9 × 10−12 C2N−1m−2, the effects of the non-conducting walls on the capacitance are negligible]