Physics Questions

Sound intensity or level is measured by a unit called a decibel. An 85 decibel noise level is not a safe standard for the public.

Hence, Acceptable noise level for human ear is less than 85 db.

Bicycle is a compound machine in the above given options. A compound machine is a machine that is formed by two or more simple machines.

As water is cooled from 4 deg C to 0 deg C, the water reaches its freezing point and starts forming ice crystals. Then the volume of that ice cubes increases and its density decreases. Hence, it is the reason that ice will float on water as ice has less density than the water.

Sound waves cannot travel through a Vacuum.

A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibrations to work in.

Astigmatism is a common vision condition that causes blurred vision. It occurs when the cornea is irregularly shaped or sometimes because of the curvature of the lens inside the eye.