Radiations present in atmosphere due to different radioactive substances are called

Alpha (α) particles are helium (He) nucleus with a charge of

A. e

B. 2e

C. 3e

D. 4e

When two light nuclei combine to form a heavier nucleus, the process is said to be

A. nuclear fission

B. nuclear fusion

C. nuclear power

D. nuclear transmutation

If a C-14 has a half-life of 5730 years, then how long will it take for the number of C-14 in a sample to drop to 1/8 of initial quantity?

A. 2.58 × 10⁴ years

B. 1.44 × 10⁴ years

C. 1.72 × 10⁴ years

D. 2.58 × 10⁴ years

In the nuclide defined by &¹⁵&₇X, the number of protons and neutrons respectively are

A. 7 and 8

B. 15 and 7

C. 8 and 6

D. 23 and 15

The elements which emit natural radioactivity are known as

A. radio elements

B. active elements

C. radioactive elements

D. nuclear elements