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Photo cells convert______ 

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Important Questions on Electronic Devices Semiconductors

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Name the optoelectronic device which convert optical radiation into electricity.

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Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Photodiodes are preferably operated in reverse bias condition for light intensity measurement.
Reason R: The current in the forward bias is more than the current in the reverse bias for a p-n junction diode.


In the light of the above statement, choose the correct answer from the options given below :

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Why photo diodes are required to operate in reverse bias? Explain.
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The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because
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Name the optoelectronic device used to detect optical signal

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Three photo diodes D1, D2 and D3 are made of semiconductors having band gaps of 2.5eV, 2eV and 3eV, respectively. Which ones will be able to detect light of wavelength 600 nm ?

Given Planck constant is h=6.62×10-34 m2 kg s-1,speed of light c=3×108 ms-1

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With the circuit diagram, distinguish between LED and photodiode. What is dark current?
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Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: Photodiodes are used in forward bias usually for measuring the light intensity.

Reason R: For a p-n junction diode, at applied voltage V the current in the forward bias is more than the current in the reverse bias for Vz>±VV0 where V0 is the threshold voltage and Vz is the breakdown voltage.

In the light of the above statements, choose the correct answer from the options given below

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Two p - n photodiodes are fabricated from semiconductors with band gap of 2.8eV and 2.6eV, respectively.

Choose the correct statement from the following.

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Consider the junction diode as ideal. The value of current flowing through AB is:
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Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V0 changes by: (assume that the Ge diode has large breakdown voltage)

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A 2V battery is connected across AB as shown in the figure. The value of the current supplied by the battery when in first case battery's positive terminal is connected to A and in second case when positive terminal of battery is connected to B will respectively be:
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In an unbiased p - n junction electrons diffuse from n-region to p-region because:
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Discuss the working of a photodiode. Why a photodiode is operated in reverse bias mode?
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Three photodiodes D1,D2 and D3 are made of semiconductors having band gaps of 2.5eV, 2eV and 3eV respectively. Which one will be able to detect light of wavelength λ=6000 Å?
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With increasing biasing voltage of a photo diode, the photocurrent magnitude: