List of top Physics Questions

In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be:
Two concentric hollow spherical shells have radii $ r $ and $ R \left(R\,>>\,r\right) $ . A charge $ Q $ is distributed on them such that the surface charge densities are equal. The electric potential at the centre is
A steady current flows in a long wire. It is bent into a circular loop of one turn and the magnetic field at the centre of the coil is $ B $ . If the same wire is bent into a circular loop of $ n $ turns, the magnetic field at the centre of the coil is
A balloon with mass m is descending down with an acceleration a (where a < g). How much mass should be removed from it so that it starts moving up with an acceleration $a$?
A stone of mass $0.05 \,kg$ is thrown vertically upwards. What is the direction and magnitude of net force on the stone during its upward motion ?
When longitudinal wave propagates, what happens in the region of compressions and rarefactions?
Period of geostationary satellite is
The equivalent resistance of two resistors connected in series is $6\, \Omega$ and their parallel equivalent resistance is $\frac{4}{3} \Omega$. What are the values of resistances ?
Einstein was awarded Nobel prize for his work in
One second is defined as
On an average, a human heart is found to beat $72$ times a minute. Its frequency and period are
An aeroplane is flying horizontally with a velocity of $360\, km\, h^{-1}$. The distance between the tips of the wings of the aeroplane is $50\, m$. The vertical component of the earth's magnetic field is $4 \times 10^{-4} \, Wb \, m^{-2}$. The induced e.m.f. is
The photoelectric threshold for a certain metal is $3600\, \mathring A$. The maximum energy of the ejected photoelectrons by radiation of $2000\, \mathring A$ is (Given $h = 6.62 \times 10^{-34} J \, s$ )
Find the energy equivalent of one atomic mass unit in joules and in $MeV$.
The mutual inductance between two coils depends upon
The normal magnetic flux passing through a coil changes with time according to the equation $\phi = 6t^2 - 5t + 1$. What is the magnitude of the induced current at $t = 0.253\, s$ and resistance $10 \, \Omega $ ?
The dimensions of energy and torque respectively are
A pump on the ground floor of a building can pump up water to fill the tank of $30\, m^3$ in $15\,min$. If the tank is $40\,m$ above the ground, and the efficiency of the pump is $30\,%$, the power consumed by the pump is $(g = 10 \, m \, s^{-2})$
Let $E _{1}( r ), E _{2}( r )$ and $E _{3}( r )$ be the respective electric fields at a distance $r$ from a point charge $Q , an$ infinitely long wire with constant linear charge density $\lambda$, and an infinite plane with uniform surface charge density $\sigma$. If $E_{1}\left(r_{0}\right)=E_{2}\left(r_{0}\right)=E_{3}\left(r_{0}\right)$ at a given distance $r_{0}$, then
Two cities are $150\, km$ apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is $8\, volt$ and the average resistance per km is $0.5\, \Omega$. The power loss in the wire is
If the focal length of objective lens is increased then magnifying power of
Hydrogen atom in ground state is excited by a monochromatic radiation of $\lambda$ = 975 $\mathring{A}$. Number of spectral lines in the resulting spectrum emitted will be
A black hole is an object whose gravitational field is so strong that even light cannot escape from it. To what approximate radius would earth (mass $= 5.98 \times 10^{24} \, kg$) have to be compressed to be a black hole?
Light with an energy flux of $ 25 \times 10^4 W m^{-2} $ falls on a perfectly reflecting surface at normal incidence. If the surface area is $ 15 c m^2 $, the average force exerted on the surface is
A projectile is fired from the surface of the earth with a velocity of $5\, m s^{- 1}$ and angle $\theta$ with the horizontal. Another projectile fired from another planet with a velocity of $3\,ms^{ - 1}$ at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet is (in $ms^{ - 2}$ ) is (Given $g= 9.8 \,ms^{ - 2}$)