Chap#20 Nuclear Physics

Question 1

The nucleus C absorbs an energetic neutron and emits a beta particle (β). The resulting nucleus is:

Answer 1

N

Question 2

The mass defect for the nucleus of helium is 0.0303 a.m.u. What is the binding energy per nucleon for helium in MeV?

Answer 2

7

Question 3

When a hydrogen atom is bombarded, the atom is excited to the n=4 state of the hydrogen atom. The energy released when the atom falls from the n=4 state to the ground state is:

Answer 3

12.75 eV

Question 4

The mass of a proton is 1847 times that of an electron. An electron and a proton are projected into a uniform electric field in a direction at right angles to the direction of the field with the same initial kinetic energy. They:

Answer 4

Both the trajectories will be equally curved

Question 5

As the electron in the Bohr orbit of the hydrogen atom passes from stat n=2 to n=1, the kinetic energy K and potential energy I change as:

Answer 5

K four-fold, U two-fold

Question 6

The half-life of a radioisotope is 5 years. The fraction of atoms decayed in this substance after 15 years will be:

Answer 6

3/4

Question 7

The structure of solids is investigated by using:

Answer 7

X-rays

Question 8

The de-Broglie wave corresponding to the particle of mass m and velocity v has a wavelength associated with it:

Answer 8

h/mv

Question 9

The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2 > W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hv > W2)

Answer 9

I1 = I2