51.

The energy released in the fission of 1 kg of ₉₂U²³⁵ is (energy per fission = 200 MeV)

• 5.1 × 10²⁶ eV

• 5.1 × 10²⁶ J

• 8.2 × 10¹³ J

• 8.2 × 10¹³ MeV

The nuclear radius of a certain nucleus is 7.2 fm and it has charge of 1.28 x 10^-17 C. The number of neutrons inside the nucleus is

• 136

• 142

• 140

• 132

Which one of the following statement is true, if half-life of a radioactive substance is 1 month ?

• 7/8^th part of the substance will disintegrate in 3 months

• 1/8^th part of the substance will remain undecayed at the end of 4 months

• The substance will disintegrate completely in 4 months

• 1/16^th part of the substance will remain undecayed at the end of 3 months

Consider the nuclear reaction X²⁰⁰ → A¹¹⁰ + B⁸⁰, If the binding energy per nucleon for X, A and B are 7.4 MeV, 8.2 MeV and 8.1 MeV respectively, then the energy released in the reaction is

• 70 MeV

• 200 MeV

• 190 MeV

• 10 MeV

The natural boron of atomic weight 10.81 is found to have two isotopes B¹⁰ and B¹¹. The ratio of abundance of isotopes in natural boron should be

• 11 : 10

• 81 : 19

• 19 : 81

• 15 : 16

Radium has a half-life of 5 yr. The probability of decay of a radium nucleus in 10 yr is

• 50 %

• 75 %

• 100 %

• 60 %

The binding energy per nucleon for deuteron and helium are 1.1 MeV and 7.0 MeV. The energy released when two deuterons fuse to form a helium nucleus is

• 23.6 MeV

• 2.2 MeV

• 30.2 MeV

• 3.6 MeV

In artificial radioactivity, 1.414 x 10⁶ nuclei are disintegrated into 10⁶ nuclei in 10 min. The half-life in minutes must be 

• 5

• 20

• 15

• 30

The half-life of radon is 3.8 days. How many radon will be left out of 1024 mg after 38 days

• 1 mg

• 2 mg

• 3 mg

• 4 mg

Which of the following is not conserved in nuclear reaction ?

• Total energy

• Mass number

• Number of fundamental particles

• Nucleon number