Nuclei

The number of beta particles emitted by radioactive substance is twice the number  of alpha particle emitted by it. The resulting daughter is an 

• isobar of parent

• isomer of parent

• isotone of parent

• isotone of parent

Two radioactive materials X₁ and X₂ have decay constant 5 λ respectively. If initially, they have the same number of nuclei, then the ratio of the number of nuclei of X₁ to that of X₂ will be 1/e after a time

• λ

• λ/2

• 1/4λ

• 1/4λ

If M (A, Z), M_P and M_n denote the masses of the nucleus   proton and neutron respectively in units of u (1 u = 931.5 MeV/c²) and BE represents its binding energy  in MeV, then

• M (A,Z) = ZM_p + (A-Z)M_n - BE/c²

• M (A,Z) = ZM_p + (A-Z)M_n + BE

• M (A,Z) = ZM_p + (A-Z)M_n - BF

• M (A,Z) = ZM_p + (A-Z)M_n - BF

Two nuclei have their mass number in the ratio of 1:3. The ratio of their nuclear densities would be

• 1:3

• 3:1

• (3)^1/3 : 1

• (3)^1/3 : 1

In radioactive decay process, the negatively charged emitted beta particles are:

• the electrons present inside the nucleus

• the electrons produced as a result  of the decay of neutrons inside the nucleus

• the electrons produced as a result of collisions between atoms

• the electrons produced as a result of collisions between atoms

A nucleus has  mass represented by  M (A, Z). If M_p and M_n denote the mass of proton and neutron respectively and BE the binding energy (in MeV), then:

• BE = [M(A,Z)-ZM_p - (A-Z)M_n]c²

• BE = [ZM_p + (A-Z)M_n -M(A,Z)]c²

• BE = [ZM_p + AM_n - M (A,Z)]c²

• BE = [ZM_p + AM_n - M (A,Z)]c²

If the nucleus  has a nuclear radius of about 3.6 fm, then  would have its radius approximately as: 

• 6.0 fm

• 9.6 fm

• 12.0 fm

• 12.0 fm

Two radioactive substance A and B have decay constants 5λ and λ respectively. At t = 0 they have the same number of nuclei. The ratio of a number of nuclei of A to those of B will be  after a time interval:

• 1/ 4λ

• 4λ

• 2λ

• 1/2λ

Monochromatic light of frequency 6.0 x 10¹⁴ Hz is produced by a laser. The power emitted is 2 x 10^-3 W The number of photons emitted, on the average, by the source per second is:

• 5 x 10¹⁵

• 5 x 10⁶

• 5 x 10¹⁷

• 5 x 10¹⁷

The binding energy of deuteron is 2.2 MeV and that of   is 28 MeV. If two deuterons are fused to form one  then the energy released is

• 25.8 MeV

• 23.6 MeV

• 19.2 MeV

• 19.2 MeV