Number of secondary neutrons emitted on fission of an atom of U-235 on slow neutron bombardment is

Consider the following statements.
In a nuclear reactor, self-sustained chain reaction is possible because
1. More neutrons are released in each of the fission reactions.
2. The neutrons immediately take park in the fission process.
3. The fast neutrons are slowed down by graphite.
4. Every neutron released in the fission reaction initiates further fission.
Which of these statements are correct?

A

Only 1, 2 and 3

B

Only 1 and 3

C

Only 2 and 4

D

Only 2, 3 and 4

Number of secondary neutron emitted on fission of an atom of U-235 by slow neutron bombardment is

A

3

B

235

C

200

D

92

What does the control rod (cadmium rod) do in a nuclear reactor? A. The fission absorbs excessive heat generated during the reaction and thus prevents excess temperature rise. B. Absorbs extra neutrons to control the chain reaction. C. Reduces the energy of neutrons so that they can be further used for the fission reaction. D. The chain produces the neutrons required for the fission reaction.

A

D

B

C

D

A

Each fission of U₂₃₅ produces following number of fast neutrons per fission

A

1 neutron

B

3 neutrons

C

1, 2 neutrons

D

2 neutrons

Fission of U-235 on slow neutron bombardment can be represented by

A

₉₂U²³⁵ + ₀n¹ → ₅₆Ba¹⁴³ + ₃₆Kr⁹⁰

B

₉₂U²³⁵ + ₀n¹ → ₅₆Ba¹⁴³ + ₃₆Kr⁹⁰ + 3 ₀n¹

C

₉₂U²³⁵ + ₀n¹ → ₅₆Ba¹⁴³ + ₃₆Kr⁹⁰ + 3 ₀n¹ + Q (energy)

D

₉₂U²³⁵ + ₀n¹ → ₉₂U²³⁶ + 3 ₀n¹+ Q (energy)

Each fission of U₂₃₅ produces on the average _________ fast neutrons as a product of reaction.

A

2.46

B

24.6

C

246

D

2460

The number of neutrons accompanying the formation of ₅₄Xe¹³⁹ and ₃₈Sr⁹⁴ from the absorption of a slow neutron by ₉₂U²³⁵ , followed by nuclear fission is

A

1

B

2

C

3

D

4

What happens when a neutron is absorbed by a nucleus of an atom of U235?

A

Mass number of atom increases

B

One electron is let out

C

U236 isotope is formed

D

Nucleus becomes unstable