Advertisements
Advertisements
प्रश्न
Colour of light emitted by LED depends upon__________________ .
- its forward bias
- its reverse bias
- the band gap of the material of semiconductor
- its size
Advertisements
उत्तर
the band gap of the material of semiconductor
APPEARS IN
संबंधित प्रश्न
With the help of a neat circuit diagram, explain the working of a photodiode.
If a small voltage is applied to a p-n junction diode, how will the barrier potential be affected when it is (i) forward biased
If a small voltage is applied to a p-n junction diode, how will the barrier potential be affected when it is(ii) reveres biased?
Using the necessary circuit diagrams, show how the V-I characteristics of a p-n junction are obtained in
Reverse biasing
How are these characteristics made use of in rectification?
Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (Eg)C, (Eg)Si and (Eg)Ge. Which of the following statements is true?
A p-n photodiode is fabricated from a semiconductor with band gap of 2.8 eV. Can it detect a wavelength of 6000 nm?
The width of depletion region of p-n junction diode is _______.
(A) 0.5 nm to 1 nm
(B) 5 nm to 10 nm
(C) 50 nm to 500 nm
(D) 500 nm to 1000 nm
State its any ‘two’ uses of photodiode.
Sunil and his parents were travelling to their village in their car. On the way his mother noticed some grey coloured panels installed on the roof of a low building. She enquired from Sunil what those panels were and Sunil told his mother that those were solar panels.
(a) What were the values displayed by Sunil and his mother? State one value for each.
(b) In what way would the use of solar panels prove to be very useful?
(c) Name the semiconductor device used in solar panels. Briefly explain with the help of a diagram, how this device works
Why is zener diode fabricated by heavily doping both p- and n-sides of the junction?
How is a photodiode fabricated?
Briefly explain its working. Draw its V - I characteristics for two different intensities of illumination ?
Draw V − I characteristics of a p-n junction diode. Answer the following questions, giving reasons:
(i) Why is the current under reverse bias almost independent of the applied potential up to a critical voltage?
(ii) Why does the reverse current show a sudden increase at the critical voltage?
Name any semiconductor device which operates under the reverse bias in the breakdown region.
Show the output waveforms (Y) for the following inputs A and B of (i) OR gate (ii) NAND gate ?
Describe briefly, with the help of a diagram, the role of the two important processes involved in the formation of a p-n junction.
How does a light emitting diode (LED) work? Give two advantages of LED’s over the conventional incandescent lamps.
What happens to the width of depletion player of a p-n junction when it is (i) forward biased, (ii) reverse biased?
Draw the circuit diagram of an illuminated photodiode in reverse bias. How is photodiode used to measure light intensity?
Explain the formation of depletion layer and potential barrier in a p−n junction.
Explain how a potential barrier is developed in a p-n junction diode.
Draw the circuit arrangement for studying the V-I characteristics of a p-n junction diode in reverse bias. Plot the V-I characteristics in this case.
Write the important considerations which are to be taken into account while fabricating a p-n junction diode to be used as a Light Emitting Diode (LED). What should be the order of the band gap of an LED, if it is required to emit light in the visible range? Draw a circuit diagram and explain its action.
The wavelength and intensity of light emitted by a LED depend upon ______.
With reference to Semiconductor Physics,
Name the process that causes depletion region in a p-n junction.
Explain photodiode.
Name the device which converts the change in intensity of illumination to change in electric current flowing through it. Plot I-V characteristics of this device for different intensities. State any two applications of this device.
A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. lt can detect a signal of wavelength ______.
For LED's to emit light in visible region of electromagnetic light, it should have energy band gap in the range of:
Which one of the following is not the advantage of LED?
Consider the following statements (A) and (B) and identify the correct answer.
- A Zener diode is connected in reverse bias when used as a voltage regulator.
- The potential barrier of the p-n junction lies between 0.1 V to 0.3 V.
If the resistance R1 is increased (Figure), how will the readings of the ammeter and voltmeter change?
Briefly explain how emf is generated in a solar cell.
Draw solar cells of I-V characteristics.
Draw the circuit diagram of an illuminated photodiode and its I-V characteristics.
How can a photodiode be used to measure light intensity?
The value of power dissipated across the Zener diode (Vz = 15 V) connected in the circuit as shown in the figure is x × 10–1 watt. The value of x, to the nearest integer, is ______.
What energy conversion takes place in a solar cell?
Identify the special purpose diodes 'A', 'B' and 'C' from the given symbols.
Consider the following statements A and B and identify the correct answer:
- For a solar-cell the I-V characteristics lies in the (IV) quadrant of the given graph.
- In a reverse biased p-n junction diode, the current measured in (μA), is due to majority charge carriers.
Consider the following statements A and B and identify the correct answer:
- For a solar-cell, the I-V characteristics lies in the IV quadrant of the given graph.
- In a reverse biased pn junction diode, the current measured in (A), is due to majority charge carriers.
