MCQ on LED ( Light Emitting Diode MCQ )

MCQ on LED (Light Emitting Diode MCQ)

If you are looking for LED Multiple Choice Questions. Here we collected some important MCQs on LED pdf. The LED mcqs pdf for class 12th and engineering students included in this page has been selected based on the popular questions asked in various competitive exams over the years. 

Light Emitting Diode MCQ


Multiple Choice Questions on LED

1. Light-emitting diodes emits light when it is in______________

(a) forward biased

b) reverse biased

c) zero biasing

d) infinite biasing

Answer: A


2. In LED light energy is emitted when_________

a) electrons fall from conduction band into holes in valence band

b) electrons fall from valence band into holes in conduction band

c)electrons and holes recombine in the forbidden energy gap

(d) both ‘b’ and ‘c’

Answer: A


3. The nature of the light emitted by LEDs depends upon

a) nature of the material used in LEDs

b) the difference in energy levels of material used

c) both ‘a and ‘b

d) neither nor ‘b’

Answer: C


4. Limiting resistance(R) is used in LED for_______

a) controlling current flowing through LED

b) controlling color of emitted light

c) both a and ‘b

d) neither a nor b

Answer: A


5. LEDs of GaAs and GaAsP release energy in_________

a) infra-red and visible region respectively

b) visible and infra-red region respectively

c) visible and ultra-violet regions respectively

d) ultra-violet and infra-red region respectively

Answer: A


6. LEDs are most popularly used because_________

a) it operates at high voltages

b) its power consumption is less

c)it is cheap and easy to handle

d) both ‘b’ and ‘c’ 

Answer: D


7. LEDs are used in______

a) visual display

b) decorative lamps in a photo frame

c) both ‘a’ and ‘b’

d) neither ‘a nor ‘b’

Answer: C


8. What is the full form of LED?

(a) Low Emitting Diode

(b) Light Emitting Diode

(c) Light-Emitting Data

(d) Light Encounter Diode

Answer: B


9. A light emitting diode is_________

(a) Heavily doped

(b) Lightly doped

(c) Intrinsic semiconductor

(d) Zener diode

Answer: A


10. Which of the following is not a characteristic of an LED?

(a) Fast action

(b) High Warm-up time

(c) Low operational voltage

(d) Long life

Answer: B


11. Which of the following materials can be used to produce infrared LED?

(a) Si

(b) GaAs

(c) CdS

(d) PbS

Answer: B


12. The LEDs made with GaAs emit light in the_________

(a) Yellow region

(b) Infrared region

(c) Orange region

(d) Red visible region

Answer: B


13. What should be the band gap of the semiconductors to be used as LED?

(a) 0.5 eV

(b) 1 eV

(c) 1.5 eV

(d) 1.8 eV

Answer: D


14. The advantage of LED is___________

(a) Long life

(b) Fast on-off switching

(c) Low operating voltage

(d) All of the above

Answer  : D


15. What is the bandwidth of the emitted light in an LED?

(a) 1 nm to 10 nm

(b) 10 nm to 50 nm

(c) 50 nm to 100 nm

(d) 100 nm to 500 nm

Answer: B


16. When forward biased, LED emits light because of___________

(a) Recombination of carriers

(b) Light generated in breaking the covalent bonds

(c) Light produced by collisions

(d) All of the above reasons

Answer: A

We hope the above MCQ on LED with answers pdf will help you during your exam preparation. If you need any assistance regarding LED mcq questions and answers pdf, feel free to ask us and we will get back to you very soon. Stay connected with for more Physics Multiple Choice Questions.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *