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161.

Half life period for carbon 14 is nearly

A.	1.2 days	B.	5.73 days
C.	5.73 years	D.	5730 days

162.

The maximum acceptable noise level in offices is

A.	10 dB	B.	40 dB
C.	75 dB	D.	100 dB

163.

The speed of sound in air is

A.	144 m/s	B.	344 m/s
C.	1344 m/s	D.	3344 m/s

164.

Which of the following pollutant affects lungs?

A.	Silica	B.	Benzene
C.	Lead	D.	Aldrin

165.

Lead is a cumulative poison which ends up in

A.	eyes	B.	eyes and ears
C.	bones and tissues	D.	legs and hands

166.

Which of the following is a cold cathode lamp?

A.	Sodium vapour lamp	B.	High pressure mercury vapour lamp
C.	Low pressure mercury vapour lamp	D.	Neon lamp

167.

While comparing tungsten filament lamps with fluorescent tubes, all of the following are the advantages in favour of tungsten filament lamp EXCEPT:

A.	Longer life	B.	Low cost
C.	More brightness	D.	Simple installation

168.

Which radio nuclide has the least half life period?

A.	Carbon 14	B.	Iodine 131
C.	Radium	D.	Hydrogen 3

169.

Type of radiation expected from earbon 14 is

A.	Alpha	B.	Beta
C.	Gamma	D.	Alpha, Beta, Gamma

170.

All of the following give Beta and Gamma radiations EXCEPT:

A.	Iridium 192	B.	Iodine 131
C.	Cobalt 60	D.	Polonium 210