For which Diode is used ?
1). modulation
2). oscillation
3). amplification
4). purification
1. The Laser is a beam of radiations which are
3. What is a compound microscope?
4. In the absence of the earth's atmosphere, sky would appear
5. Which one type of radiation has the longest wave length
6. Why does a black board appears black in colour?
7. Soap bubble attains spherical shape due to ________