Question:
The I-\(V\) characteristic of an \(LED\) is
The I-\(V\) characteristic of an \(LED\) is
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An LED is a forward-biased p-n junction: negligible current up to a threshold voltage, then a rapid exponential rise; the threshold depends on the colour.
Updated On: Nov 13, 2026
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The Correct Option is A
Solution and Explanation
An LED is a p-n junction diode operated in forward bias, so its I-V curve starts at the origin, stays very small up to a threshold (knee) voltage and then rises steeply (exponentially) with V.
The threshold voltage is larger for light of higher frequency (shorter wavelength): red LEDs have the lowest threshold and blue the highest, so the curves for different colours are shifted along the V axis.
Option (1) shows four forward-bias curves rising with V, shifted for different colours. Option (2) shows I falling with V (not a diode curve), option (3) shows a tunnel-diode-like negative resistance region, and option (4) has I and V axes in a reverse/odd arrangement with I decreasing.
Answer: (1)
The threshold voltage is larger for light of higher frequency (shorter wavelength): red LEDs have the lowest threshold and blue the highest, so the curves for different colours are shifted along the V axis.
Option (1) shows four forward-bias curves rising with V, shifted for different colours. Option (2) shows I falling with V (not a diode curve), option (3) shows a tunnel-diode-like negative resistance region, and option (4) has I and V axes in a reverse/odd arrangement with I decreasing.
Answer: (1)
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