Physics

Assuming the disc is uniform and isotropic (the same in different directions), the hole will expand in the same ratio as the metal. It is because the thermal expansion equation applies to all lengths associated with the metal, including the circumference of the hole, since the edge of the hole is made out of metal. And if the circumference of the hole expands, so does the diameter.

The splitting of different colours of light in a prism is disperson of light.

The fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by Johannes Kepler.

Superconductors are substances which display zero electrical resistance when a current is supplied, and are able to propagate such a current in a circuit indefinitely.

Slip rings are usually made of Phosphor Bronze.

Energy travels from Sun to Earth through radiation.

The escape velocity of the rocket in the earth is 11.2 km/sec.

It takes 80 calories to melt 1 gram of ice. If 1 g of ice (at 0 degrees Celsius) is given 80 calories, it will melt and the final temperature of the water will be 0. Freezing water at 0 degrees Celsius: It also takes 80 calories to freeze 1 gram of water.

The period of revolution of a geostationary satellite is 24 hours.

When two ice cubes are pressed together, they join to form one cube due to hydrogen bond.