
Photo cells convert______

Important Questions on Electronic Devices Semiconductors


Name the optoelectronic device which convert optical radiation into electricity.

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



Name the optoelectronic device used to detect optical signal


Three photo diodes and are made of semiconductors having band gaps of and , respectively. Which ones will be able to detect light of wavelength ?
Given Planck constant is ,speed of light


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 junction diode, at applied voltage the current in the forward bias is more than the current in the reverse bias for where is the threshold voltage and is the breakdown voltage.
In the light of the above statements, choose the correct answer from the options given below

Two - photodiodes are fabricated from semiconductors with band gap of and respectively.
Choose the correct statement from the following.




and diodes start conducting at and respectively. In the following figure if diode connection are reversed, the value of changes by: (assume that the Ge diode has large breakdown voltage)







