List of top Physics Questions

If the resultant of all external forces acting on a system of particles is zero, then from an inertial frame one can surely say that:
The nucleus of a helium atom travels along the inside of a straight hollow tube 4 m long which forms part of a particle accelerator. If one assumes uniform acceleration, how long is the particle in the tube if it enters at a speed of 2000 m/s and leaves at 8000 m/s?
The acceleration due to gravity at a height of 7 km above the earth is the same as at a depth \( d \) below the surface of the earth. Then \( d \) is:
The molecules of a given mass of a gas have root mean square speed of 120 m/s at 88°C and 1 atmospheric pressure. The root mean square speed of the molecules at 127°C and 2 atmospheric pressure is:
A tentative explanation of observations without assuming that it is true is called:
Two black bodies P and Q have equal surface areas and are kept at temperatures \( 127^\circ C \) and \( 27^\circ C \) respectively. The ratio of thermal power radiated by A to that by B is:
In the head-on collision of two alpha particles \( \alpha_1 \) and \( \alpha_2 \) with the gold nucleus, the closest approaches are 31.4 fermi and 94.2 fermi respectively. Then the ratio of the energy possessed by the alpha particles \( \alpha_2 / \alpha_1 \) is:
The SI unit of electrical conductivity is:
The time dependence of a physical quantity \(P\) is given by \[ P = P_0 \exp(-\alpha t^2) \] where \(\alpha\) is a constant and \(t\) is time. The constant \(\alpha\) will:
What will be the change in wave length, if a light of wave length 600 nm travels from air enters a medium of refractive index 1.5 and continues its journey through that medium?
In the Young's double slit experiment the fringe width of the interference pattern is found to be \(3.2 \times 10^{-4}\) m, when the light of wavelength 6400 \(\text{Å}\) is use(D) What will be the change in fringe width if the light is replaced with a light of wavelength 4800 \(\text{Å}\)?
A resistor of wire 24 cm length and resistance 8Ω is stretched into a uniform wire of 48 cm length, then the new resistance will be:
Two open organ pipes A and B of length 22 cm and 22.5 cm respectively produce 2 beats per sec when sounded together. The frequency of the shorter pipe is:
The ground state energy of hydrogen atom is -13.6 eV. If the electron jumps from the 3rd excited state to the ground state, then the energy of the radiation emitted will be:
A metallic rod of 10 cm is rotated with a frequency 100 revolution per second about an axis perpendicular to its length and passing through its one end in a uniform transverse magnetic field of strength 1 T. The emf developed across its ends is:
220 V ac is more dangerous than 220 V d(C) Why?
An uniform sphere of mass \( M \) and radius \( R \) exerts a force of \( F \) on a small mass \( m \) placed at a distance of \( 3R \) from the centre of the sphere. A spherical portion of diameter \( R \) is cut from the sphere as shown in the fig. The force of attraction between the remaining part of the disc and the mass \( m \) is:
A particle at rest decays into two particles of mass \( m_1 \) and \( m_2 \) and move with velocities \( v_1 \) and \( v_2 \). The ratio of their de Broglie wave lengths \( \lambda_1 : \lambda_2 \) is:
A lens of power \( +1 \, \text{D} \) is made in contact with another lens of power \( -2 \, \text{D} \). The combination will then act as:
The magnetic permeability \( \mu \) of a paramagnetic substance is:
The electric flux from a cube of side 1 m is \(\Phi\). When the side of the cube is made 3 m and the charge enclosed by the cube is made one-third of the original value, then the flux from the bigger cube will be:
If the ratio of specific heat of a gas at constant pressure to that at constant volume is \( \gamma \), the change in internal energy of a mass of a gas when the volume changes from \( V \) to 3\( V \) at constant pressure is:
If reaction is \(R\) and coefficient of friction is \(\mu\), what is the work done against friction in moving a body by distance \(d\)?
When the angle of incidence on one face of the equilateral glass prism is \(\frac{3}{4}\) of the angle of the prism, the ray of light undergoes minimum deviation. If the velocity of light in vacuum is \(c\), then the velocity of light in the glass is:
A magnetic field does not interact with: