List of top Physics Questions

Explain the differences between \( n \)-type and \( p \)-type semiconductors. Show that both types of semiconductors are electrically neutral.
Obtain the formula for the intensity of electric field on the equatorial point of an electric dipole.
Explain refraction of light by Huygens wave theory, when waves enter from denser to rarer medium.
What is Gauss' law? Find the formula for the intensity of electric field produced due to a point charge with the help of it.
The equivalent capacitance is 20 \( \mu \)F by joining two capacitors of capacitances \( C_1 \) \( \mu \)F and \( C_2 \) \( \mu \)F in parallel. If they are joined in series, the equivalent capacitance is 4.8 \( \mu \)F. Find the ratio of the capacitances \( C_1 \) and \( C_2 \) ( \( C_1>C_2 \)).
What is displacement current? A plane electromagnetic wave of 25 MHz frequency is propagating along the x-axis in vacuum. The electric field at any point in the vacuum is \( \vec{E} = 6 \hat{j} \) volt/metre. What is the magnitude and direction of the magnetic field \( \vec{B} \) at this point?
When does the force acting between two parallel and straight current carrying conductors become (i) attractive and (ii) repulsive and why?
Find the ratio of de-Broglie wavelength associated with a proton and an \( \alpha \)-particle having the same kinetic energy.
Define mass defect and binding energy.
What is meant by angle of polarisation?
Define 1 henry of self-inductance.
Obtain the formula of the relationship of drift velocity and potential difference.
Write the definition and unit of current density.
The unit of \( \sqrt{LC} \) (where \( L \) is inductance and \( C \) is capacitance) is:
In the given nuclear process, particle \( W \) is: \[ ^2\text{He}^4 + _zX^A \rightarrow _{z+2}Y^{A+3} + W \]
Write the expression and unit of magnetic dipole moment.
In order to pass 10\% of the main current in a galvanometer of resistance \( R \), the required resistance of shunt should be:
Threshold wavelength for a photoelectric cell is \( \lambda_0 \). If the work-function of the cathode of some other cell becomes \( n \) times that of the first cell, then threshold wavelength for the other cell will be:
What are the microwaves? State one use of them.
The refracting angle of a prism of refractive index \( \sqrt{3} \) is equal to its angle of minimum deviation. The value of angle of minimum deviation is:

Write the definition and dimensional formula of electrical conductivity. 
 

Which value of current does the ammeter used in A.C. circuit measure? 
 

Find the value of 1 kWh in Joules. 
 

A double convex lens is made of a material having refractive index 1.2. Both the surfaces of the lens are convex. If it is dipped into water of refractive index 1.33, it will behave like: 
 

Differentiate between interference and diffraction of light. Explain qualitatively the diffraction phenomenon of light by a single slit. Light of 6000 Ã… wavelength is incident normally on a single slit of width \( 3 \times 10^{-4} \, \text{cm} \). Find out the angular width of the central maxima.