If M is atomic mass, A is mass number of a nucleus, then $\frac{\mathrm{M} - \mathrm{A}}{\mathrm{A}}$ is called

• mass defect

• fermi energy

• binding energy

• packing fraction

The half-life of a radio-isotope is 4 h. If initial mass of the isotope was 200 g, then mass remaining after 24 h will be

• 1.042 g

• 2.084 g

• 3.125 g

• 4.167 g

183.

A radioactive nucleus A finally transforms into a stable nucleus B. Then A and B can be

• isobars

• isotones

• isotopes

• none of these

If ₉₂U²³⁸ emits 8 $\mathrm{\alpha }$-particles and 6 β-particles, then the resulting nucleus is

• ₈₂U²⁰⁶

• ₈₂Pb²⁰⁶

• ₈₂U²¹⁰

• ₈₂U²¹⁴

C¹⁴ has half-life 5700 yr. At the end of 11400 yr, the actual amount left is

• 0.5 of original amount

• 0.25 of original amount

• 0.125 of original amount

• 0.0625 of original amount

Li nucleus has three protons and four neutrons. Mass of lithium nucleus is 7.016005 amu. Mass of proton is 1.007277 amu and mass of neutron is 1.008665 amu. Mass defect for lithium nucleus in amu is

• 0.04048 amu

• 0.04050 amu

• 0.04052 amu

• 0.04055 amu

Which of the following is not conserved in nuclear reaction ?

• Total energy

• Mass number

• Charge number

• Number of fundamental particles

The number of $\mathrm{\alpha }$-particles and β-particles respectively emitted in the reaction ₈₈A¹⁹⁶ →  ₇₈B¹⁶⁴ are

• 8 and 8

• 8 and 6

• 6 and 8

• 6 and 6

The counting rate observed from a radioactive source at t = 0 was 1600 count/s and at t = 8 s it was 100 counts/s. The counting rate observed as counts per second at t = 6 s, will be

• 400

• 300

• 250

• 200

Which of the following statement is correct ?

• The rest mass of a stable nucleus is less than the sum of the rest masses of its separated nucleons.

• The rest mass of a stable nucleus is greater than the sum of the rest masses of its separated nucleons.

• In nuclear fission, energy is released by fusion two nuclei of medium mass (approximately 1O0 amu).

• In nuclear fission, energy is released by fragmentation of a very low nucleus.