The LED:
1. is reverse-biased.
2. is forward-biased.
3. can be made of \(\mathrm{GaAs}\).
4. both (2) & (3) are correct.

Subtopic:  Applications of PN junction |
 70%
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Zener diode is not used for:
1. oscillatory circuit
2. current amplification
3. voltage amplification
4. all of the above
Subtopic:  Applications of PN junction |
 70%
From NCERT
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A Zener diode when used as a voltage regulator is connected:
i. in forward bias   
ii. in reverse bias
iii. in parallel with the load 
iv. in series with the load
Choose the correct option:
1. (i) and (ii) are correct
2. (ii) and (iii) are correct
3. only (i) is correct
4. only (iv) is correct
Subtopic:  Applications of PN junction |
 88%
From NCERT
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Given below are two statements:
Assertion (A): The resistance of a photodiode decreases when light having photons of sufficient energy is incident on it.
Reason (R): When energetic photons fall on the \(\mathrm{p\text{-}n}\) junction of a photodiode, electron-hole pairs are created due to the breaking of the valence bonds.
 
1. (A) is True but (R) is False.
2. (A) is False but (R) is True.
3. Both (A) and (R) are True and (R) is the correct explanation of (A).
4. Both (A) and (R) are True but (R) is not the correct explanation of (A).
Subtopic:  Applications of PN junction |
 70%
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For the above circuit, the applied voltage \(V(t)\) is periodic and linear, and is shown by the waveform below:
    
The current flowing through \(R_2\) varies as:
 
1. 2.
3. 4.
Subtopic:  Applications of PN junction |
 55%
From NCERT
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