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.

The submerged portion of the ice on melting shrinks a little in volume. so the level of water goes down a little.But this is just made up by the water added by the melting of upper portion. Addition is equal to the Shrinkage. Hence level is unchanged.

Flows out of Newton's first law of motion.

Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.

• Kepler?s three laws of planetary motion can be stated as follows:

(1) All planets move about the Sun in elliptical orbits, having the Sun as one of the foci.

(2) A radius vector joining any planet to the Sun sweeps out equal areas in equal lengths of time.

(3) The squares of the sidereal periods (of revolution) of the planets are directly proportional to the cubes of their mean distances from the Sun.

We know that,

The equivalent K =   L 1 + L 2 L 1 K 1 + L 2 K 2

where L1 & L2 are plate1 & Plate2 thicknesses, K1 & K2 are coefficient thermal conductivity of plate1 & Plate2 respectively.

But here L1 = L2 = L (say)

Then K = L+L/(L/K1 + L/K2)  =   2 K 1 K 2 K 1 + K 2

The path that data takes from source to destination is called a Channel. A channel is a communication medium. A channel has a certain capacity for transmitting information. 

The "capacity" of a channel is the theoretical upper-limit to the bit rate over a given channel that will result in negligible errors. Channel capacity is often measured by its Bandwidth in Hz or its data rate in bits per second.