List of top Physics Questions asked in UP Board XII

 The atomic mass of \( ^{16}O \) is 16.0000 amu. Calculate its binding energy per nucleon. Mass of electron = 0.00055 amu, mass of proton = 1.007593 amu, mass of neutron = 1.008982 amu, and 1 amu = 931 MeV. 
 

 Explain the operation of p-n junction diode in forward bias. 
 

A double concave lens has to be made from crown glass. How much should the radii of surfaces of lens be kept to make the power of lens -2.5 D? Refractive index of crown glass is 1.65. 
 

Define the mass defect and binding energy of nucleus. 
 

Between radio waves and microwaves, which one has a higher frequency? 
 

 How much charge is there on a hole? Draw the circuit symbol of p-n junction diode. 
 

In hydrogen atom, what is the ionization potential of the electron in the ground state? 
 

Find the ratio of the focal length of lens in air and that of lens when it is immersed in liquid. 
 

Force of 80 Newton works between two point charges placed at a fixed distance apart in air. When these charges are placed at the same distance apart in a dielectric medium, then the force of 8 Newton works on it. The dielectric constant of the medium will be: 
 

The power consumed in alternating current in a circuit containing only a capacitor will be: 
 

 The maximum focal length of convex lens is for: 
 

The path of scattered \( \alpha \)-particle is: 
 

If drift velocity of electron be \( v_d \) and intensity of electric field \( E \), then which relation among the following obeys Ohm's law?
The Louis de Broglie wavelength of a particle having kinetic energy E is:

A moving charge produces: 
 

Electric charges are uniformly distributed in a small volume. The flux of electric field through a spherical surface of radius 2 cm surrounding the total charge is 10 V x m. The flux over a sphere of radius 4 cm will be:

Calculate the conductivity of an n-type semiconductor from the following data: Density of conduction electrons = \( 8 \times 10^{13} \, \text{cm}^{-3} \) Density of holes = \( 5 \times 10^{12} \, \text{cm}^{-3} \) Mobility of electrons = \( 2.3 \times 10^4 \, \text{cm}^2/\text{V-s} \) Mobility of holes = \( 100 \, \text{cm}^2/\text{V-s} \)
Explain postulates of Bohr's model for Hydrogen atom. Show the number of lines in the (A) emission and (B) absorption spectra of Hydrogen atom corresponding to transition between energy states \(n = 1\) and \(n = 4\).
Explain image formation in a reflecting telescope with the help of a ray diagram. Compare its qualities with a refracting telescope.
Calculate the following in the given circuit:
(A) The equivalent capacitance of the circuit.
(B) The charge on \( 3 \, \mu\mathrm{F} \) and \( 2 \, \mu\mathrm{F} \) capacitors.
\includegraphics[]{equivalent capac.PNG}

State and explain Gauss's law in electrostatics. Using it, find the electric field due to a uniformly charged thin spherical shell (charge = q and radius = R) at 

(A) external point of shell 

(B) internal point of shell 

(C) on the surface of shell. 
 

Find the maximum magnitude of velocity and linear momentum of a photoelectron emitted when light of wavelength 4000 Ã… falls on a metal having work function 2.5 eV. 
 

What is interference of light? Mention the condition for (A) constructive and (B) destructive interference. 
 

Explain Maxwell's displacement current and write its equation. What is the phase difference between it and the conduction current? 
 

A coil has a resistance of 10 Ω and inductance of 0.4 Henry. It is connected to an AC source of 6.5 V, 30 Hz. Find the average power consumed in the circuit.