1000+ General Knowledge Questions and Answers in English - 3

Question: 11

Mention some applications of lenses?

Lenses are used in optical instruments like simple microscope (magnifying glass), compound microscope, camera, telescope etc.

Question: 12

What are the two kinds of spherical mirror?

The two kinds of spherical mirrors are concave mirror and convex mirror.

Question: 13

What is spectrum?

The seven different colours formed due to dispersion is known as spectrum. They are violet, blue, green, yellow, orange and red (VIBGYOR).

Question: 14

What is twinkling of stars?

The brighter and fainter appearance of the star with varying time is called the twinkling of the stars.

Question: 15

What is mirage?

A mirage is an optical illusion observed in deserts or over hot extended surfaces like a coal tarred road.