A certain mass of hydrogen is changed to helium the process of fusion. The mass defect in fusion reaction is 0.02866 u. The energy liberated per u is (given 1 u =931 MeV)

• 2.67 MeV

• 26.7 MeV

• 6.675 MeV

• 13.35 MeV

C.

6.675 MeV

A proton carrying 1 MeV kinetic energy is moving in a circular path of radius R in the uniform magnetic field. What should be the energy of an alpha particle to describe a circle of the same radius in the same field.

• 2 MeV

• 1 MeV

• 0.5 MeV

• 4 MeV

B.

1 MeV

An electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths λ₁:λ₂ emitted in the two cases is

• 7/5

• 27/20

• 27/5

• 20/7

An electron of a stationary hydrogen atom passes from the fifth energy level to ground level. The velocity that the atom acquired as a result of photon emission will be

• 
• 
• 
• 

A.

Consider 3^rd orbit of He⁺ (Helium)_, using non-relativistic approach, the speed of electron in this orbit will be (given K= 9 x 10⁹ constant, Z=2 and h (Planck's constant = 6.6 x 10^-34 Js^-1

• 2.92 x 10⁶ m/s

• 1.46 x 10⁶ m/s

• 0.73 x 10⁶ m/s

• 3.0 x 10⁸ m/s