Question:

Radioactive disintegration of uranium ultimately results in formation of –

A.

radium

B.

thorium

C.

polonium

D.

lead

Answer» d. lead

Question:

The most abundant element in the human body is –

A.

carbon

B.

iron

C.

nitrogen

D.

oxygen

Answer» d. oxygen

Question:

Impure camphor is purified by –

A.

sublimation

B.

fractional crystallisation

C.

fractional distillation

D.

steam distillation

Answer» a. sublimation

Question:

Greenhouse effect is caused by –

A.

nitrogen

B.

carbon dioxide

C.

carbon monoxide

D.

nitrogen dioxide

Answer» b. carbon dioxide

Question:

In which following processes light energy is converted into chemical energy?

A.

Respiration

B.

Fermentation

C.

Photosynthesis

D.

Photorespiration

Answer» c. Photosynthesis

Question:

Polythene is industrially prepared by the polymerization of –

A.

Methane

B.

Styrene

C.

Acetylene

D.

Ethylene

Answer» d. Ethylene