Explore topic-wise MCQs in Electronics & Communication Engineering.

This section includes 7 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

Examples of an active display and a passive display respectively are

A. LCD and Gas discharge plasma
B. LED and LCD
C. Gas discharge plasma and LED
D. Electrophoretic Image display and LED
Answer» C. Gas discharge plasma and LED
Discussion
2.

A 100 W light source emits uniformly in all directions. A photodetector having a circular active area whose diameter is 2 cm is placed 1 m away from the source, normal to the incident light. If the responsivity of the photodetector is 0.4 A/W, the photo-current generated in the detector, in units of mA, is

A. 1
B. 4
C. 100
D. 400
Answer» B. 4
Discussion
3.

In LED, light is emitted because:

A. Light falls on LED
B. Recombination of charges takes place
C. PN junction emits light when heated
D. IR light falls on LED
Answer» C. PN junction emits light when heated
Discussion
4.

_______ current is the leakage current that flows through a photo diode with no input used in as light detectors.

A. Leakage
B. Dark
C. saturation current
D. Detection
Answer» C. saturation current
Discussion
5.

LEDs fabricated from GaAsP emit radiations in the

A. infra-red region
B. ultraviolet region
C. visible region
D. none of these
Answer» D. none of these
Discussion
6.

Identify the given image.

A. Light dependent resistor
B. Metal film resistor
C. Carbon film resistor
D. Wire wound resistor
Answer» E.
Discussion
7.

A low resistance LDR of 20Ω, operated at a certain intensity of light, is to be protected through a series resistance in such a way that up to 12 mA of current is to flow at a supply voltage of 10 V. What is the nearest value of the protective resistance?

A. 873 Ω
B. 813 Ω
C. 273 Ω
D. 81 Ω
Answer» C. 273 Ω
Discussion