Electromagnetic Waves — Physics STD 12 Science — Question

A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866u. The energy liberated per u is (Given 1 u = 931MeV)

A straight copper wire is moved in a uniform magnetic field such that it cuts the magnetic lines of force. Then

Mark the correct options:

If a comb is rubbed on dry hairs, and then brought near paper pieces, it:

Assertion  : The electromagnetic waves of shorter wavelength can travel longer distances on earth's surface than those of longer wavelengths.
Reason      :  Shorter the wavelength, the larger is the velocity of wave propagation.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

The resistance of a metal increases with increasing temperature because:

The kinetic energy force on the particle continuously increases with time.

1. The resultant force on the particle must be parallel to the velocity at all instants.
2. The resultant force on the particle must be at an angle less than 90° all the time.
3. Its height above the ground level must continuously decrease.
4. The magnitude of its linear momentum is increasing continuously.

How many coulombs of electricity must pass through acidulated water to liberate 22.4 litres of hydrogen at N.T.P.?

If a lens is cut into two pieces perpendicular to the principal axis and only one part is used, the intensity of the image