List of top Physics Questions

In to a uniform transverse magnetic field, two charged particles having the same mass and charge enter and move in two different circular paths. The ratio of the radii of curvatures of the circular paths is $ 1 : 4 $. What would be the ratio of their respective velocities?

Fusion reaction is more energetic than fission reaction because

The electric field versus distance graph is shown as given. Select the correct statement from the following.
E – electric field, R – radius, r – distance from the centre

Two spherical planets $ P $ and $ Q $ have the same uniform density $ \rho $, and masses $ M_P $ and $ M_Q $, and surface areas $ A $ and $ 4A $ respectively. Another spherical planet $ R $ also has the same uniform density $ \rho $, and its mass is $ M_P + M_Q $. The escape velocities from these planets is

To get 300 MW electric power for half an hour, how much mass is to be completely converted into energy?

What is the dimensional formula for electric flux?

One end of a nylon rope of length $ 1 $ and diameter $ 10 \, \text{mm} $ is fixed to free limb. A monkey weighing $ 100 \, \text{N} $ jumps to catch the free end and stays there. The change in diameter of the rope is (Young's modulus of the wire is $ Y $ and Poisson Ratio is $ \sigma $)

The value of universal gravitational constant was first determined by

A wind mill converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. The electrical power output $ P $ is related to the velocity of wind $ v $ as

A current of 2 A is passed through the primary coil. The total flux linked with the secondary coil, which is closely wound over the primary is $ 2000 \times 10^{-6} \, \text{weber} $. What is the induced emf in the secondary if the current through the primary increases at a rate of $ 0.2 \, \text{A s}^{-1} $?

A bullet of momentum $ p $ is fired into a door and gets embedded exactly at the center of the door. The door is $ 1.0 \, \text{m} $ wide and weighs $ 12 \, \text{kg} $. It is hinged at one end and rotates about a vertical axis practically without friction. The angular speed of the door just after the bullet embeds into it is:

Three point charges $ -1C, +1C, +1C $ are placed at points $ A, B, C $ respectively of a triangle $ ABC $. What is the total potential energy of the system? [given $ AB = AC = 6 \, \text{cm} $ and $ BC = 3 \, \text{cm} $]

A beam of light parallel to the principal axis of a concave and convex lens, first passes through the concave lens of focal length $ 0.5 \, \text{m} $ and then through the convex lens of focal length $ 1.75 \, \text{m} $. If the lenses are placed $ 1.25 \, \text{m} $ apart, which of the given statement is true?

Water from a tap emerges vertically downwards with an initial speed of $ 1.0 \, \text{ms}^{-1} $. The cross-sectional area of the tap is $ 1 \, \text{cm}^2 $. Assume that the pressure is constant throughout the stream of water and that the flow is steady. The cross-sectional area of the stream $ 15 \, \text{cm} $ below the tap is $ (g = 10 \, \text{ms}^{-2}) $

When a body of refractive index $ \mu = 1.4 $ is put into a liquid, the body becomes invisible. What would be the refractive index of the medium?

Three ideal diodes and resistors connected to the cell of negligible internal resistance is as shown. Find the current passing through the $ 10\Omega $ resistor.

A particle 'X' carrying a charge $ +Q $ is moving in a circular path of radius $ R $ around another particle 'Y' having a charge $ -Q $ with a frequency $ \nu $. Then the mass $ m $ of the charged particle is:

A car, starting from rest, accelerates at the rate $ f $ through a distance $ S $, then continues at constant speed for some time $ t $ and then decelerates at the rate $ \frac{f}{2} $ to come to rest. If the total distance is $ 5S $, then

A coin is placed on a disc rotating with an angular velocity $ \omega $. The co-efficient of friction between the disc and the coin is $ \mu $. The maximum distance of the coin from the centre of the disc up to which it will rotate with the disc is

A circular coil of area $ 2\sqrt{2} \, \text{cm}^2 $ and resistance $ 2\Omega $ is arranged vertically in the east-west direction. A uniform magnetic field $ 0.2 \, \text{T} $ is set up across the plane in the north to east direction. Now the magnetic field is removed at a steady rate in $ 0.4 \, \text{s} $. What is the current developed in the coil?

To obtain the given truth table, the following logic gate should be placed at G:

The relationship between the magnetic susceptibility $ \chi $ and the magnetic permeability $ \mu $ is given by:
$ \mu_0 $ is the permeability of free space and $ \mu_r $ is relative permeability.

A wire of resistance 4 $\Omega$ is used to make a coil of radius 7 cm. The wire has a diameter of 1.4 mm and the resistivity of its material is 2 x 10$^{-7}$ $\Omega$ m. The number of turns in the coil will be

The average energy of a neutron produced in the fission of $ ^{235}_{92}U $ is

In an oscillating spring mass system, a spring is connected to a box filled with sand. As the box oscillates, sand leaks slowly out of the box vertically so that the average frequency Ï‰(t) and average amplitude A(t) of the system change with time t. Which one of the following options schematically depicts these changes correctly?