List of top Physics Questions

Two lenses, one diverging of power 2D and the other converging of power 6D are combined together. Calculate the focal length and power of combination.
Find the focal length of the combination of two thin lenses in contact.
Calculate the resistivity of the material of a conductor of length 3 m, area of cross section \( 0.2 \, \text{mm}^2 \) having a resistance of 2 \( \Omega \).
Calculate the Coulomb’s force between proton and electron separated by a distance of \( 0.8 \times 10^{-15} \) m.
What are the factors which reduce the efficiency of a transformer?
What is displacement current?
What is resistance? Define SI unit of resistance.
Derive an expression for magnetic force. How is the direction of magnetic force determined?
Write an expression for mass defect.
The density of nuclear matter is independent of the size of the nucleus. (T/F)
The size of the mirror does not affect the nature of the image. (T/F)
Define threshold wavelength and frequency.
Calculate the de-Broglie wavelength for electrons moving with speed of \( 10^5 \, \text{m/s} \).
Why can’t two equipotential surfaces intersect each other?
Diffraction of light is the phenomenon of bending of light around the corners of an aperture in its path. (T/F)
Wheatstone bridge is used to measure:
The laws of electromagnetic induction have been used in the construction of:
The ultimate individual unit of magnetism in any magnet is:
The strength of a bar magnet is maximum at its center. (T/F)
A semiconductor is a device that obeys Ohm's law. (T/F)
In the Bohr model of the hydrogen atom, the lowest orbit corresponds to:
On doping, the conductivity of a semiconductor:
If a dielectric is kept between two plates of a capacitor, its capacitance:
When the distance between the charges is halved, the force between the charges becomes:
Applying forward bias in a p-n junction, the potential barrier: