Question

Positrons are spontaneously emitted from the nuclei of

(1) potassium-37 (3) nitrogen-16
(2) radium-226 (4) thorium-232

Answer 1

Positrons are spontaneously emitted from the nuclei of potassium -37.

Answer 2

Answer: Option (1) is the correct answer.

Step-by-step explanation:

• A positron is a small particle which contains a +1 charge and its mass is equal to the mass of an electron, that is,
  `9.109 * 10^(-31)` kg.

A positron is represent by the symbol
`^(0)_(+1)\beta`.

For example,
`^(37)_(19)K \rightarrow ^(37)_(18)Ar + ^(0)_(+1)\beta`

• Whereas nitrogen-16 does not decay to give a positron because nitrogen-16 is the daughter isotope formed due to decay of oxygen-16.

The decay reaction is as follows.

`^(16)_(8)O \rightarrow ^(16)_(7)N + ^(0)_(+1)\beta`

• And, on radioactive decay of thorium-232 there will be formation of radium-228 along with emission of an alpha particle.

The reaction will be as follows.

`^(232)_(90)Th \rightarrow ^(228)_(88)Ra + ^(4)_(2)\alpha`

Therefore, we can conclude that out of the given options positrons are spontaneously emitted from the nuclei of potassium-37.