The question asks about the specific method a DVD uses for storing and reading data.
A DVD (Digital Versatile Disc) is a type of optical disc storage medium.
Therefore, the correct method used by DVDs is optical.
Match the following :
| List – I | List – II |
| a. LASER | i. Emits monochromatic light of low intensity |
| b. Solar cell | ii. Consumes electrical power due to tHe incident light |
| c. Photo diode | iii. Delivers power to load |
| d. LED | iv. Emits monochromatic light of high intensity |
Codes :
Which one of the following is not LED material ?
1. Ga As
2. Ga P
3. Si
4. SiO2
When atoms in Direct bandgap semiconductors move from higher energy state (E2) to lower energy state (E1) and emission of light takes place, the energy of emitted photon is given as