Questions

Light travels Faster than Sound.

Light :

1. Light doesn't require a medium to travel.

2. It travels in the vaccum with the speed of 1,86,000 miles per second.

Sound:

1. Sound rquire a medium.

2. It travels in the Air with the speed of 340 meters per second.

3. It travels Faster in Water than in Air.

4. It travels Faster in Steel than in Water. 

Electrical Pressure is also called as Voltage. Voltage is measured in Volts.

Volt : A unit of electrical pressure or Voltage is called Volt.

One volt is the amount of pressure required to cause one ampere of current to flow against one ohm of resistance.

Voltage is also referred to as Electromotive Force or Electrical Potential or Electrical Pressure.

Sea appears blue in colour due to the scattering of the rays when they hit water molecules

Here are the differences between Diamond and Graphite :

From the above analysis, Diamond is harder than Graphite because of the difference of crystalline structures.