List of top Physics Questions

Two metal spheres, one of radius $ \frac{R}{2} $ and the other of radius $ 2R $ respectively have the same surface charge density. They are brought in contact and separated. The ratio of their new surface charge densities is:

Two charges $ -q $ each are fixed, separated by distance $ 2d $. A third charge $ q $ of mass $ m $ placed at the mid-point is displaced slightly by $ x' (x \ll d) $ perpendicular to the line joining the two fixed charges as shown in the figure. The time period of oscillation of $ q $ will be:

The formula for refractive index of a prism is
The least distance of distinct vision of a healthy person is
The appearance of red colour of the Sun during Sunrise and Sunset is due to
A convex lens kept in a medium with refractive index less than the refractive index of the lens behaves like
The process of an eye lens to adjust its focal length to form a sharp image on retina is called
The width of the fringes obtained in the Young's double slit experiment is 2.6 mm when light of wavelength 6000$^\circ$A is used. If the whole apparatus is immersed in a liquid of refractive index 1.3 the new fringe width will be:
Two circular coils of radius 'a' and '2a' are placed coaxially at a distance 'x' and '2x' respectively from the origin along the X-axis. If their planes are parallel to each other and perpendicular to the X-axis and both carry the same current in the same direction, then the ratio of the magnetic field induction at the origin due to the smaller coil to that of the bigger one is:
Though Sn and Si are 4th group elements, Sn is a metal while Si is a semiconductor because
A conductor of length 'l' is moving perpendicular to magnetic field 'B' with a speed 'v'. The motional emf is given by -
Which law states "the induced current set up in the coil is in such a direction that it opposes the changes in the flux"?
Induction stove works on the principle of
Which one of the following statements is correct?
A one kg block of ice at $ -1.5^\circ C $ falls from a height of 1.5 km and is found melting. The amount of ice melted due to fall, if 60% energy is converted into heat is (Specific heat capacity of ice is 0.5 cal g$^{-1}$ C$^{-1}$, Latent heat of fusion of ice = 80 cal g$^{-1}$)
The closest approach of an alpha particle when it makes a head-on collision with a gold nucleus is $ 10 \times 10^{-14} $ m. Then the kinetic energy of the alpha particle is:

If potential (in volt) in a region is expressed as $ V(x, y, z) = 6xy - y + 2yz $, the electric field (in} $ \text{N/C} $ at point (1, 0, 1) is:

Which of the given dimensional formula represents heat capacity?
A circular coil of radius 0.1 m is placed in the X-Y plane and a current 2 A is passed through the coil in the clockwise direction when looking from above. Find the magnetic dipole moment of the current loop.
A cubical box of side 1 m contains Boron gas at a pressure of 100 Nm$^{-2}$. During an observation time of 1 second, an atom travelling with the rms speed parallel to one of the edges of the cube, was found to make 500 hits with a particular wall, without any collision with other atoms. The total mass of gas in the box in gram is:
A string of length 25 cm and mass $ 10^{-3} $ kg is clamped at its ends. The tension in the string is 2.5 N. The identical wave pulses are generated at one end and at regular interval of time, $ \Delta t $. The minimum value of $ \Delta t $, so that a constructive interference takes place between successive pulses is:
The midpoint of a thin lens is called
The current in a conductor is directly proportional to the potential difference between its ends at constant temperature. This is known as
The S.I. unit of electrical resistance is
The direction of the magnetic field lines outside the current carrying solenoid is from