Common Observations

Long-distance telephone becomes easier

More telephones can be used

Transmission is easier

Reception is cheaper

It has double walls

It has silver coated walls

Heat losses by conduction and radiation are largely prevented

Air between the double walls is removed

Oil is very light

Of the diffusion of oil through the wick

Oil is volatile

Of the capillary action phenomenon

Reflects

Absorbs

Refracts

Scatters

Two blankets have more wool and hence, provide greater warmth

Two blankets enclose air which does not allow the cold to perpetrate

Two blankets compress the air in between the body and the blankets and this compression produces heat

None of these

The antibiotics inside a refrigerator kill bacteria and fungus

Bacteria and fungus can not multiply fast at sufficiently low temperatures

The low temperature inside makes the food shrink and thereby crush the germs

Refrigerator contains food preservatives that get activated at low temperatures

Of higher density of pure water

Of higher density of salty water

Egg shell is made of calcium which is heavier than pure water

The fluid matter inside the egg has the same density as the salty water

Reflection of blue sky by seawater and scattering of blue light by water molecules

Reflection of the blue light by the impurities in sea water

Absorption of other colours by water molecules

None of these

High pressure

Low pressure

Absence of air

Its weak gravitational power

The atmospheric pressure at high attitude is less compared to what is at the sea level

The atmospheric pressure at high attitude is more than what is at the sea level

The atmospheric pressure is exactly the same as that at the sea level

The atmospheric pressure keeps changing rapidly