Practice MCQ Questions and answers on Physics-GK

Because flying takes a tremendous amount of energy, birds need to get lots of oxygen. The extra air sacs in their lungs help them to keep fresh air flowing in, unlike mammals, where the “old” air within the trachea and mouth (which has low oxygen content and high CO² levels) in inhaled each time. Birds eliminate this “anatomical dead space” problem by using air sacs.

When a barometer reading suddenly recedes, it indicates that climate will be extremely stormy.

When a barometer is rising air pressure is increasing.

The pressure exerted by a 760 mm column of mercury at 0 °C is known as "Pascal".

­A barometer measures air pressure: A "rising" barometer indicates increas­ing air pressure; a "falling" barometer indicates decreasing air pressure.

Barometer is instrument which is used to measure to pressure. A slow downfall of reading suggests a low pressure area is passing in a nearby region, it may rain. If the reading is going down very fast then its an indication of storm (within 5-6 hours).

The increased wind speed is accompanied by low/reduced air pressure.

Vacuum cleaners work by creating a lower pressure just inside the opening which touches the floor. Because there is no, or very little, atmosphere on the moon, we can't create a lower or higher gas pressure inside and outside the machine, so dirt cannot be sucked up from the ground.

Cyclones are fueled by the temperature differences (hence pressure gradients) that exist along frontal boundaries. They are usually strongest during cold months when temperature differences between air masses can be most extreme.

Skating on ice is possible because the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water.