List of top Physics Questions

In 1st case, Carnot engine operates between temperatures 300 K and 100 K. In 2nd case, as shown in the figure, a combination of two engines is used. The efficiency of this combination (in 2nd case) will be:

Fig.
A man weighing 70 kg is riding on a cart of mass 30 kg which moves along a level floor at a speed of 3 ms-1. If he runs on the cart so that his velocity relative to the cart is 4ms-1 in the direction opposite to the motion of the cart, the speed of centre of mass of the system is

In the circuit shown, assume the diode to be ideal. When \( V_i \) increases from \(-2V\) to \(6V\), the change in current is (in mA): 

The work done by a force on body of mass 5 kg to accelerate it in the direction of force from rest to 20 m/s2 in 10 second is

A satellite of mass ‘m’ is revolving around the earth of mass ‘M’ in an orbit of radius ‘r’. The angular momentum of the satellite about the centre of orbit will be

A car is moving with a speed of 54 km / h. If after 3 s, the driver applies brakes and it stops, then how much distance is covered by the car before coming to rest?
An object is placed at the principal focus of a concave lens of focal length 10 cm. The image will be formed at___ cm, between the optical center and the focus of the lens on the same side of the object.
What is the maximum number of hydrogen bonds that a water molecule can make in the liquid state?
Calculate the temperature (in K) at which the resistance of a metal becomes 20% more than its resistance at 300 K. The value of the temperature coefficient of resistance for this metal is \(2.0 \times  10^{-4}\)/K.
A man throws a ball vertically up in the air with an initial velocity v1 such that it reaches a height of 12 m with a speed of 12 m/s. If he throws the same ball vertically up with an initial velocity v such that it reaches a maximum height of 12 m. Calculate v1/v2 (up to 2 decimal places).
What is the acceleration due to gravity (m/s²) on the surface of a planet if its radius is 1/4th that of earth and its mass is 1/80th that of earth" Assume that the gravity on the surface of the earth is 10 m/s².
The potential difference to accelerate an electron was quadrupled. By what factor does the de Broglie wavelength of the electron beam change?
A 500 nm light is used for imaging in a confocal microscope. What will be the best resolution (in nm) of this microscope?

The electric potential \( V(x) \) in a region around the origin is given by \( V(x) = 4x^2 \, {volts}. \) .The electric charge enclosed in a cube of 1m side with its center at the origin is (in coulomb)

In a region, steady and uniform electric and magnetic fields are present. These two fields are parallel to each other. A charged particle is released from rest in this region. The path of the particle will be a
An object is thrown vertically upwards. At its maximum height, which of the following quantity becomes zero?
A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be
The magnetic field of a plane electromagnetic wave is given by: \[ \vec{B} = 2 \times 10^{-8} \sin \left(0.5 \times 10^3 x + 1.5 \times 10^{11} t \right) \hat{j} \, {T}. \] {The amplitude of the electric field would be:}
The self-induced emf of a coil is 25 volts. When the current in it is changed at uniform rate from 10A to 25 A in 1s, the change in the energy of the inductance is:
A vertical electric field of magnitude \( 4.9 \times 10^5 \, {N/C} \) just prevents a water droplet of a mass \( 0.1 \, {g} \) from falling. The value of charge on the droplet will be: (Given \( g = 9.8 \, {m/s}^2 \))

A thermodynamic system is taken from an original state D to an intermediate state E by the linear process shown in the figure. Its volume is then reduced to the original volume from E to F by an isobaric process. The total work done by the gas from D to E to F will be:
 

A particle is moving with a velocity \( \vec{v} = K (y \hat{i} + x \hat{j} )\), where \( K \) is a constant. The general equation for its path is:
The de Broglie wavelength of a proton and \( \alpha \)-particle are equal. The ratio of their velocities is:
If \( E \) and \( H \) represent the intensity of electric field and magnetizing field respectively, then the unit of \( \frac{E}{H} \) will be:
If two soap bubbles of different radii are connected by a tube: