Which one among the following methods is not effective in removing arsenic from contaminated groundwater?
Boiling
Reverse osmosis
Ion exchange
Coagulation-adsorption
A.
Boiling
To obtain the powerful parallel beams of light from a vehicle's headlight, one must use
front surface silvered plane mirror
back surface silvered plane mirror
concave mirror
convex mirror
Which one among the following denotes the smallest temperature?
1° on the Celsius scale
1° on the Kelvin scale
1° on the Fahrenheit scale
1° on the Reaumur scale.
A fan produces a feeling of comfort during hot weather, because
our body radiates more heat in air
fan supplies cool air.
conductivity of air increases
our perspiration evaporates rapidly