List of top Physics Questions

Two charges \(5\) nC and \(-2\) nC are placed at points \( (5,0,0) \) and \( (23,0,0) \) in a region of space where there is no other external field. The electrostatic potential energy of this charge system is:
The frequency of fifth harmonic of a closed pipe is equal to the frequency of third harmonic of an open pipe. If the length of the open pipe is 72 cm, then the length of the closed pipe is:
Which one of the following is not classified as pulse modulation?

In the given figures of logic gates, if the inputs are A=1, B=0, and C=1, find the values of \( y_1 \), \( y_2 \), and \( y_3 \) respectively. 

 

The work done by an ideal gas of 2 moles in increasing its volume from \( V \) to \( 2V \) at constant temperature \( T \) is \( W \). The work done by an ideal gas of 4 moles in increasing its volume from \( V \) to \( 8V \) at constant temperature \( \frac{T}{2} \) is
The efficiency of a heat engine that works between the temperatures where Celsius-Fahrenheit scales coincide and Kelvin-Fahrenheit scales coincide is (approximately):
Energy required to remove an electron from an aluminium surface is 4.2 eV. If light of wavelength 2000 Å falls on the surface, the velocity of the fastest electron ejected from the surface will be
In a sport event a disc is thrown such that it reaches its maximum range of 80 m, the distance travelled in first 3 s is (g = 10ms\(^2\))
The average power generated by a 90 kg mountain climber who climbs a summit of height 600 m in 90 minutes is (Acceleration due to gravity \( g = 10 \) m/s\(^2\)):
Two cylindrical vessels A and B of different areas of cross-section kept on the same horizontal plane are filled with water to the same height. If the volume of water in vessel A is 3 times the volume of water in vessel B, then the ratio of the pressures at the bottom of the vessels A and B is:
A block of mass \(m\) is placed in equilibrium on a moving horizontal plank. The maximum horizontal acceleration of the plank for \(\mu = 0.2\) is (Acceleration due to gravity = \(10 \, {ms}^{-2}\)).
The capacitance of an isolated sphere of radius \( r_1 \) is increased by 5 times when enclosed by an earthed concentric sphere of radius \( r_2 \). The ratio \( \frac{r_1}{r_2} \) is:

Two bar magnets A and B are identical and arranged as shown. Their lengths are negligible compared to the separation between them. A magnetic needle placed between the magnets at point P gets deflected through an angle \( \theta \) under their influence. The ratio of distances \( d_1 \) and \( d_2 \) is: 


 

A person climbs up a conveyor belt with a constant acceleration. The speed of the belt is \( \sqrt{\frac{g h}{6}} \) and the coefficient of friction is \( \frac{5}{3\sqrt{3}} \). The time taken by the person to reach from A to B with maximum possible acceleration is: \includegraphics[]{87.png}
An aircraft executes a horizontal loop of radius 1 km with a speed of 900 kmph. Then, the ratio of its centripetal acceleration to the acceleration due to gravity is:
A ray of light travels from an optically denser to rarer medium. The critical angle for the two media is \( C \). The maximum possible deviation of the ray will be:
In case of diffraction, if \( a \) is a slit width and \( \lambda \) is the wavelength of the incident light, then the required condition for diffraction to take place is:

In the following diagram, the work done in moving a point charge from point P to point A, B and C are \( W_A, W_B, W_C \) respectively. Then (A, B, C are points on semicircle and point charge \( q \) is at the centre of semicircle)
 

The ground state energy of hydrogen atom is -13.6 eV. The potential energy of the electron in this state is:
If the work done in stretching a wire by 1 mm is 2 J, the work necessary for stretching another wire of same material but with double radius of cross section and half the length by 1 mm is
If the current through an inductor increases from 2 A to 3 A, the magnetic energy stored in the inductor increases by
The Poisson’s ratio of a material is 0.4. If the force is applied to a wire of this material, there is a decrease of cross-sectional area by 2%. The percentage increase in its length is:
A substance of mass \( m \) requires a power input of \( P \) to remain in the molten state at its melting point. When the power is turned off, the sample completely solidifies in time \( t \). The latent heat of the substance is

In a Carnot engine, the absolute temperature of the source is 25% more than the absolute temperature of the sink. The efficiency of the engine is

One mole of a gas having \( \gamma = \frac{7}{5} \) is mixed with one mole of a gas having \( \gamma = \frac{4}{3} \). The value of \( \gamma \) for the mixture is ( \( \gamma \) is the ratio of the specific heats of the gas)