List of top Physics Questions

What is Gauss' law? Find the formula for the intensity of electric field produced due to a point charge with the help of it.
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.
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.
Define 1 henry of self-inductance.
What is meant by angle of polarisation?
Write the definition and unit of current density.
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:
In order to pass 10\% of the main current in a galvanometer of resistance \( R \), the required resistance of shunt should be:
What are the microwaves? State one use of them.
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.
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. 
 

What is meant by the transformation ratio of a transformer? In a step-down transformer, the transmission line voltage of 2200 volt is changed to 220 volt. Number of turns in the primary coil is 5000. The efficiency of the transformer is 90 percent and output power is 8kW.

Two parallel plate capacitors of capacitances \( C \) and \( 2C \) are joined with a battery of voltage difference \( V \) as shown in the figure. If the battery is removed and the space between the plates of the capacitor of capacitance \( C \) is completely filled with a material of dielectric constant \( K \), then find out:

  • i) Total capacitance of the combination
  • ii) Final voltage difference across the combination
  • iii) Total energy stored in the combination.