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MHT CET202618 April 2026Morning ShiftPhysicsSemiconductorsActual

Which one of the following statements is 'WRONG' regarding LED?

Options

  1. ALED's have long lifetime if properly manufactured.
  2. BColours produced by LED's do not fade out.
  3. CLED's are energy efficient.
  4. DBrightness of light emitted by LED cannot be controlled.

Correct answer

D. Brightness of light emitted by LED cannot be controlled.

Step-by-step solution

The brightness of light emitted by an LED is directly proportional to the forward current flowing through it. By varying the forward current or by using techniques like Pulse Width Modulation (PWM), the brightness of an LED can be easily controlled. Therefore, the statement 'Brightness of light emitted by LED cannot be controlled' is incorrect. The other statements are correct: LEDs are highly energy-efficient, have a long operational lifetime, and their emitted colours are generally stable and do not fade out.

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