Top 1000+ GK Questions and Answers Pdf - 3

Question: 11

Define optic centre of a lens?

The geometric centre of the lens is called Optic centre (O).

Question: 12

How are shadows formed?

When an opaque object is placed between the source of light and the screen, shadow is formed because the light rays travel in straight line.

Question: 13

What are the differences between camera and eye?

Camera

Eye

It has lens with variable focal length.

Camera

The image is inverted.

Eye

The image is erect.

Question: 14

What is regelation?

The phenomenon of refreezing is called regelation.

Question: 15

Distinguish between heat and temperature?

Heat

1. Heat denotes the amount of heat energy contained in a body.

2. It depends upon the speed of the particles.

3. It depends on the number of particles, size and type of particles.

4. It is measured in joule.

Temperature

1. Temperature denotes the degrees of hotness or coldness of a body.

2. It depends upon the average speed of the molecules.

3. It does not depend on the size or type of particles of the object.

4. It is measured in degrees Celsius or Kelvin.