Practice MCQ Questions and answers on Physics-GK

Surface tension of oil is smaller than that of water. When oil is dropped on the surface of water, the force stretches the oil drops on all sides. Hence the oil spreads over the surface of water.

Rotameter is used to measure flow of fluids.

Siphon will fail to work if the level of the liquid in the two vessels are at the same height. Siphon is a tube bent to form two legs of unequal length by which a liquid can be transferred from a reservoir and then down to a lower level of it.

Bernoulli’s principle states that as the speed of a moving fluid (liquid or gas) increases, the pressure within the liquid decreases. In the case of a sprayer, when the plunger is pushed in, the air flows at a high velocity through a nozzle, creating a region of low pressure above the metal tube. The higher pressure of the atmospheric air causes the liquid to rise up to the metal tube and come out as spray.

A drop of liquid assumes spherical shape because a sphere has the least surface area for a given volume.

The liquid surface falls down on the direction of motion and rises up on the back side of the tank.

The lift of an aeroplane is caused by Bernouli's theorem.

Tensiometer is used to measure Soil Water Tension.

Blotting paper absorbs ink by the process of capillary action. The capillary action is based on the property of surface tension of liquid.
All unsized paper will absorb water. Blotting paper is not sized and made bulkier to provide capillary action for faster absorption of liquid.
Blotting paper has also been sold as a cosmetic to aid in the removal of skin oils and makeup.

Effervescence is the escape of gas from an aqueous solution and the foaming or fizzing that results from a release of the gas. It leads to the formation of gas bubbles in a liquid. For example, when opening a bottle of champagne, beer or carbonated beverages such as soft drinks, the visible bubbles are produced by the escape from solution of the dissolved gas.