Physics Test - 52

The speed of light will be minimum while passing throughglass.

The Surface tension pulls the surface of the drop equally at all points thus produces the spherical shape having the minimum surface area. This surface tension is the "skin" of a body of water that makes the molecules stick together.

To produce deflection in a television picture tube a magnetic field is used.

Aluminium being a good conductor of heat conducts away the heat from the substance quite easily and causes quick freezing.

Parallactic secondis not the unit of time.

If a sound travels from air to water, the quantity that remain unchanged is frequency.

The Sound Following the flash of lighting is because of Thunder.

Lightning is seen earlier than thunder because light travels much faster than sound.

The roar of thunder is the result of a shock wave produced when lightning super-heats the air through which it passes, causing that air to expand very rapidly. This rapid expansion of air creates a shock wave that travels outward at close to the speed of sound.

Both warmth and moisture reduce the density of air and hence its pressure is high.

The core of an electromagnet is made of soft iron because soft iron haslarge susceptibility and small retentivity.

Masses of stars and galaxies are usually expressed in terms of solar mass.