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प्रश्न
Briefly explain how emf is generated in a solar cell.
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उत्तर
Process of emf generation in a solar cell:
- Light falls on the junction. Electron-hole pairs are generated.
- The electron and hole move in opposite directions due to the junction field. Electrons move towards the n-side and holes move towards the p-side of the junction.
- The two sides of the junction become oppositely charged and a photovoltage is generated.
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संबंधित प्रश्न
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?
With what considerations in view, a photodiode is fabricated? State its working with the help of a suitable diagram.
Even though the current in the forward bias is known to be more than in the reverse bias, yet the photodiode works in reverse bias. What is the reason?
Using the necessary circuit diagrams, show how the V-I characteristics of a p-n junction are obtained in
Forward biasing
How are these characteristics made use of in rectification?
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
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.
How does a light emitting diode (LED) work? Give two advantages of LED’s over the conventional incandescent lamps.
Explain the three processes involved in the working of a solar cell.
Explain photodiode.
The amplifiers X, Y and Z are connected in series. If the voltage gains of X, Y and Z are 10, 20 and 30, respectively and the input signal is 1 mV peak value, then what is the output signal voltage (peak value)
- if dc supply voltage is 10V?
- if dc supply voltage is 5V?
Identify the special purpose diodes 'A', 'B' and 'C' from the given symbols.
