List of top Physics Questions

The temperature at which the rms speed of hydrogen molecules is same as the rms speed of oxygen molecules at a temperature of $6495^\circ$C is
At room temperature, two bubbles of radii 8 cm and 15 cm are connected by a capillary tube. The final radii of the two bubbles respectively are (Neglect the volume of the air in the capillary tube)
10 g of ice at $-20^\circ$C is dropped into a calorimeter of water equivalent 20 g, containing 10 g of water at $20^\circ$C. At equilibrium, the mass of the ice in the mixture is
The Reynolds number and nature of flow of water flowing with a velocity of $10~\text{cm s}^{-1}$ through a pipe of diameter $1.8~\text{cm}$ is (Coefficient of viscosity of water $=10^{-3}~\text{Pa s}$)
One end of a steel wire of length 2 m is attached to the roof and the other end is loaded with 2 kg mass. Another steel wire of same thickness but 1 m in length is held horizontally and stretched by applying two 20 N forces at its two ends. The ratio of the elongations produced in the two wires is (Acceleration due to gravity = $10~\text{ms}^{-2}$)
When a bullet is fired with a velocity of $150~\text{m s}^{-1}$ at a target of thickness 50 cm, it emerges with a velocity of $100~\text{m s}^{-1}$. If another bullet of same mass is fired with same velocity at a second target of thickness 80 cm, then the velocity with which the bullet emerges from the second target is (Retarding forces are equal in both the cases)
A body of mass 50 g is projected vertically upwards from the ground. If the kinetic energy of the body at a height of 32 m is 100% more than its potential energy, then the height at which the potential energy of the body becomes 60% of its kinetic energy is
A car of mass 1100 kg is moving on a straight rough horizontal surface with a speed of 43.2 kmph. If the coefficient of friction between the surface and the tyres of the car is 0.3, then the shortest distance in which the car can come to rest is (Acceleration due to gravity = $10~\text{m s}^{-2}$)
The minimum velocity of a projectile is 50% of its maximum velocity. If the minimum velocity of the projectile is $10~\text{m s}^{-1}$ then the time of flight of the projectile is (Acceleration due to gravity = $10~\text{m s}^{-2}$
The ratio of the masses of two thin uniform circular discs made of same material having same thickness is 4:9. The ratio of the moments of inertia of the two discs about their diameters is
A body is falling freely under gravity from a certain height from the ground. If the sum of the displacements of the body in the second and third seconds of its motion is 32% of the height from which it is falling, then the speed with which the body hits the ground is (Acceleration due to gravity = $10~\text{m s}^{-2}$)
The fundamental force in nature which operates among heavier elementary particles only is
Which of the following statements is not correct regarding significant figures?
Optical communication using fibres is performed in the frequency range of:
In a common emitter amplifier, the collector resistance is 3 times the base resistance. If the common emitter current amplification factor is 60, then the power gain of the amplifier is:
The intrinsic carrier concentration of a semiconductor is $1.2\times10^{16}$ m$^{-3}$. On doping with an impurity, the electron concentration becomes $20\times10^5$ times initial concentration. The concentration of holes in the doped semiconductor is:
If the de Broglie wavelength of a proton accelerated through a potential difference $V_1$ is same as the de Broglie wavelength of an alpha particle accelerated through $V_2$, then $V_1 : V_2 = $
The ratio of frequencies of second line of Lyman series and third line of Balmer series of hydrogen atom is:
A resistor of resistance 160 $\Omega$, an inductor of 280 mH, and a capacitor are connected in series to an AC source of 80 V, 50 Hz. If the circuit is in resonance, the potential difference across the capacitor is:
If the energy released in the fission of one uranium nucleus is 200 MeV, then the number of fissions per second required to produce 20 MW is:
The potential difference between the plates of a parallel plate capacitor is changing at the rate of $3.5\times10^6$ V/s. If the displacement current is 7 A, the capacitance of the capacitor is:
If the half-life of a radioactive material is 5 days, then the ratio of the number of atoms disintegrated in 10 and 15 days is:
Two charged particles enter a uniform magnetic field normally. If the ratio of the specific charges of the two particles is 2:3, then the ratio of the times taken by the two particles to complete one revolution is:
A train is moving with a speed of 198 kmph. If the distance between the rails is 120 cm and the vertical component of earth's magnetic field is $0.25 \times 10^{-4}$ T, the induced emf between the ends of the axle of the train is:
The magnetic field (in $10^{-4}$ T) at the centre of a toroid of mean radius 10 cm with 200 turns and carrying a current of 2.5 A is: