Q.11. Which one of the following statements is WRONG regarding LED?
A. LEDs are energy efficient
B. LEDs have long time if properly manufactured.
C. Brightness of light emitted by LED cannot be controlled.
D. Colours produced by LED do not fade out.
Answer :- C.Brightness of light emitted by LED cannot be controlled.
Explanation :-
The statement that is WRONG regarding LED is:
Option C: Brightness of light emitted by LED cannot be controlled.
This statement is incorrect because the brightness of LEDs can indeed be controlled. The brightness of an LED is directly proportional to the current passing through it. Thus, by adjusting the current, we can dim or brighten an LED. This can be achieved by various methods such as pulse-width modulation (PWM), which rapidly turns the LED on and off to control the average amount of light being emitted without changing its color, or by using a current limiting resistor or a constant current source to directly adjust the current. Advanced lighting systems also make use of digital controls to regulate the intensity of LED lighting.
Let’s briefly evaluate the other options to understand why they are considered correct:
Option A: LEDs are energy efficient – This is true. LEDs use much less energy compared to traditional incandescent bulbs for the same amount of light output, making them a more energy-efficient lighting solution.
Option B: LEDs have long life if properly manufactured – This statement is correct as well. LEDs can have a very long lifespan, often up to 25,000-50,000 hours, provided they are well-manufactured and used within their specified operating conditions.
Option D: Colours produced by LED do not fade out – LEDs maintain their color throughout their lifespan. Unlike some traditional lighting options that can change color as the filament wears out or the gas in the bulb is depleted, LEDs do not suffer from this issue and thus the colors remain consistent.