The nucleus  ${}_{\mathrm{n}}{}^{\mathrm{m}}\mathrm{X}$ emits one $\mathrm{\alpha }$  particle and 2β- particles. The resulting nucleus is

• ${}_{\mathrm{n}-2}{}^{\mathrm{m}-4}\mathrm{Y}$

• ${}_{\mathrm{n}-4}{}^{\mathrm{m}-6}\mathrm{Z}$

• ${}_{\mathrm{n}}{}^{\mathrm{m}-6}\mathrm{Z}$

• ${}_{\mathrm{n}}{}^{\mathrm{m}-4}\mathrm{X}$

Assertion:  More energy is released in fusion than fission. 

Reason:  More number of nucleons take part in fission.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Asserion: γ-radiation emission occurs after $\mathrm{\alpha } \mathrm{and} \mathrm{\beta }$ decay.

Reason: Energy levels occurs in nucleus.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

94.

The ratio of the masses of the elements having their nuclear radii 2 fermi and 1 fermi

• 8

• 2

• 3

• 4

A proton travels few distance in an electric field, then it enters a crossed magnetic field of 1 T and radius 0.2 m, find the velocity of proton

• 0.2 × 10⁸ m s^-1

• 0.2 ×  10⁷ m s^-1

• 0.2 ×  10⁶ m s^-1

• 2 ×  10⁷ m s^-1

For a nuclear reactor to run in critical condition the reproduction factor k should be

• = 1

• > 1

• < 1

• >>> 1

S³² absorbs energy and decays into which element after two $\mathrm{\alpha }$-emissions?

• Carbon

• Aluminium

• Oxygen

• magnesium

Among the following which is used to control the rate of reaction of nuclear fissions reactions?

• Water

• Heavy water

• Cadmium

• Graphite

Assertion:  For nuclear reactor, it is desirable to have k = 1.

Reason: Sustained chain reaction occur at this critical condition.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Mass defect in nuclear reactions is less than 1%.

Reason: In nuclear reaction change in BE/N is generally less than 1%.

• If both assertion and reason are true and reason is correct explanation of asertion.

• If both assertion and reason are true and reason is not correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.