List of top Physics Questions

In a transformer, number of turns in the primary are 140 and that in the secondary are 280 . If current in primary is $4 A$, then that in the secondary is :

A tuning fork arrangement (pair) produces $4$ beats/s with one fork of frequency $288\, cps$. A little wax is placed on the unknown fork and it then produces $2$ beats/s. The frequency of the unknown fork is :

Initial angular velocity of a circular disc of mass $M$ is $\omega_{1}$. Then two small spheres of mass $m$ are attached gently to two diametrically opposite points on the edge of the disc. What is the final angular velocity of the disc?

The potential difference applied to an X-ray tube is 5 kV and the current through it is 3.2 mA. Then the number of electrons striking the target per second is

An ideal gas is taken through the cycle A $\rightarrow$ B $\rightarrow$ C $\to$ A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C $\rightarrow$ A is

An ideal black-body at room temperature is thrown into a furnace. It is observed that

A simple pendulum is oscillating without damping. When the displacement of the bob is less than maximum, its acceleration vector a is correctly shown in

A particle, which is constrained to move along x-axis, is subjected to a force in the same direction which varies with the distance x of the particle from the origin as F (x) $=-kx+ax^3$. Here, k and a are positive constants. For $x \ge 0$, the functional form of the potential energy U (x) of the particle is

A long straight wire along the z-axis carries a current I in the negative z-direction. The magnetic vector field B at a point having coordinate (x, y ) on the z = 0 plane is

A circular platform is free to rotate in a horizontal plane about a vertical axis passing through its centre. A tortoise is sitting at the edge of the platform. Now the platform is given an angular velocity ${\omega}_0$ When the tortoise move along a chord of the platform with a constant velocity (with respect to the platform). The angular velocity of the platform $\omega (t)$ will vary with time t as

A long horizontal rod has a bead which can slide along its length and is initially placed at a distance L from one end A of the rod. The rod is set in angular motion about A with a constant angular acceleration $\alpha$. If the coefficient of friction between the rod and bead is $\mu$, and gravity is neglected, then the time after which the bead starts slipping is

A siren placed at a railway platform is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz, while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of the velocity of train B to that of train A is.

A geostationary satellite orbits around the earth in a circular orbit of radius $36,000\, km$. Then, the time period of a spy satellite orbiting a few hundred km above the earth's surface $ (R_ e = 6400km) $ will approximately be

When a particle is rotating in a circle will happen:

Two vessels A and B of cross-section as shown in figure contain a liquid upto the same height. As the temperature rises, the liquid pressure at the bottom (neglecting expansion of the vessels) will:

For a gas undergoing an adiabatic process, the relation between temperature and volume is found to be $ T{{V}^{0.4}}= $ constant. This gas must be:

During an experiment, an ideal gas is found to obey an additional law $ V{{P}^{2}}= $ constant. The gas is initially at a temperature T, and volume V. When it expands to a volume 2V, the temperature becomes:

The amplification factor of a triode depends on the: