List of top Physics Questions

A 3 kg block is connected as shown in the figure. Spring constants of two springs \( K_1 \) and \( K_2 \) are 50 Nm\(^{-1}\) and 150 Nm\(^{-1}\) respectively. The block is released from rest with the springs unstretched. The acceleration of the block in its lowest position is ( \( g = 10 \) ms\(^{-2}\) )

The moment of inertia of a solid sphere of mass 20 kg and diameter 20 cm about the tangent to the sphere is:

A wooden plank of mass 90 kg and length 3.3 m is floating on still water. A girl of mass 20 kg walks from one end to the other end of the plank. The distance through which the plank moves is

A particle is executing simple harmonic motion with a time period of 3 s. At a position where the displacement of the particle is 60% of its amplitude, the ratio of the kinetic and potential energies of the particle is:

The acceleration due to gravity at a height of 6400 km from the surface of the earth is \(2.5 \, \text{ms}^{-2}\). The acceleration due to gravity at a height of 12800 km from the surface of the earth is (Radius of the earth = 6400 km)

The radius of cross-section of the cylindrical tube of a spray pump is 2 cm. One end of the pump has 50 fine holes each of radius 0.4 mm. If the speed of flow of the liquid inside the tube is 0.04 m/s, the speed of ejection of the liquid from the holes is:

In a cold storage, ice melts at the rate of 2 kg per hour when the external temperature is 20°C. The minimum power output of the motor used to drive the refrigerator which just prevents the ice from melting is (latent heat of fusion of ice = 80 cal g\(^{-1}\))

A Carnot engine has the same efficiency between 800 K and 500 K, and \( x>600 \) K and 600 K. The value of \( x \) is:

The angle between the electric dipole moment of a dipole and the electric field strength due to it on the equatorial line is:

In a hydrogen atom, an electron is making \( 6.6 \times 10^5 \) revolutions around the nucleus of radius \( 0.47 \) Å. The magnetic field induction produced at the center of the orbit is nearly:

Any magnetic material loses its magnetic property when it is:

A resistance of \( 20 \Omega \) is connected to a source of an alternating potential \( V = 200 \sin(10\pi t) \). If \( t \) is the time taken by the current to change from the peak value to the rms value, then \( t \) is (in seconds):

The average value of electric energy density in an electromagnetic wave is: [where \( E_0 \) is the peak value]

A nucleus with atomic mass number \( A \) produces another nucleus by losing 2 alpha particles. The volume of the new nucleus is 60 times that of the alpha particle. The atomic mass number \( A \) of the original nucleus is:

A PN junction diode is used as:

A body thrown vertically upwards reaches a maximum height \( H \). The ratio of the velocities of the body at heights \( \frac{3H}{4} \) and \( \frac{8H}{9} \) from the ground is:

The equation of projectile motion is given by \( y = 3x - 0.8x^2 \). The time of flight of the projectile is (Acceleration due to gravity \( g = 10 \) m/s²):