In beta plus decay

• antineutrino is produced with electron

• neutrino is produced with positron

• neutron is produced with electron

• none of these

Assertion:  ${}_{27}{}^{60}\mathrm{Co}$  is a source of gamma radiation.

Reason: Gamma emission is due to nuclear decay.

• 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.

Half life of a radio-active element is 8 years, how much amount will be present after 32 years?

• $\frac{1}{4}$

• $\frac{1}{8}$

• $\frac{1}{16}$

• $\frac{1}{32}$

Gamma decay takes place

• Prior to alpha decay.

• Prior to beta decay.

• Prior to positron decay.

• Due to de-excitment of nuclear levels.

215.

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.

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