18. Compared to visible red light emitting diode, an infrared LED :
(a)Produces light with longer wavelength (b)Produces light with shorter wavelength (c)Produces light with medium wavelength (d)Produces light of all wavelengths
Answer
Answer : (a)
Explanation
Explanation : No answer description available for this question. Let us discuss.
19. In comparison to LED, LASER has :
1. High emission frequency
2. No tuning arrangement
3. Narrow spectral bandwidth
4. Provision for confinement
Of these statements
(a) 1, 3, & 4 are correct (b) 1, 2, & 3 are correct (c) 1 & 3 are correct (d) 2, 3, & 4 are correct
Answer
Answer : (c)
Explanation
Explanation : No answer description available for this question. Let us discuss.
20. Match the items in Group I with items in Group II most suitably
Group I Group II
(P) LED (1) Heavily doped
(Q) Avalanche photo diode (2) Coherent radiation
(R) Tunnel diode (3) Spontaneous emission
(S) LASER (4) Current gain
Opto Electronics » Exercise - 136. When the light increases, the reverse current in a photo-diode : (a) increases (b) decreases (c) is unaffected (d) none of the above
Opto Electronics » Exercise - 132. When the light increases, the reverse current in a photo-diode : (a) increases (b) decreases (c) is unaffected (d) none of the above
Opto Electronics » Exercise - 118. Compared to visible red light emitting diode, an infrared LED : (a) Produces light with longer wavelength (b) Produces light with shorter wavelength (c) Produces light with medium wavelength (d) Produces light of all wavelengths
Opto Electronics » Exercise - 1 1. Consider the following statements 1. LED is also known as direct gap diode. 2. LCD generates light. of these statements : (a) 1 is correct but 2 is wrong (b) 2 is correct but 1 is wrong (c) both 1 & 2 are correct (d) both 1 & 2 are wrong