Physics

Mica is used in electrical appliances such as electric iron because mica is a good conductor of heat but a bad conductor of electricity.

Birds don’t get electrocuted on power lines because electricity does not move through their bodies when they sit on them. When the bird sits with both its feet on the electrical wire, their legs have an equal electrical potential so the electricity will not move throughout the bird’s body.

The hertz (Hz) is defined as one cycle per second and is a SI unit of frequency. Here kilohertz is also a unit of frequency of waves and is defined as 1000 cycles per second. Radio waves are measured in kilohertz (KHz).

As sunlight passes through the atmosphere, all UVC and approximately 90% of UVB radiation is absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA radiation is less affected by the atmosphere. Therefore, the UV radiation reaching the Earth’s surface is largely composed of UVA with a small UVB component.

Hydraulic brakes in automobile work on Pascal’s principle.

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 CO levels) in inhaled each time. Birds eliminate this “anatomical dead space” problem by using air sacs.

Intensity of sound has an object existence.

The phenomenon of change in direction of light when it passes from one medium to another is called refraction.

At high altitudes, oxygen molecules are further apart because there is less pressure to “push” them together. This effectively means there are fewer oxygen molecules in the same volume of air as we inhale.