Case Study:

Read the following paragraph and answer the questions.

When p side of p-n junction is connected to positive terminal of battery and n side of p-n junction is connected to negative terminal of battery then the p-n junction is said to be in forward bias mode or forward biased. And When p side of p-n junction is connected to negative terminal of battery and n side of p-n junction is connected to positive terminal of battery then the p-n junction is said to be in reverse bias mode or reverse biased. The diode used to rectify an AC voltage is called as rectifier. Zener diode is also a p-n junction diode which works in reverse bias condition and used as voltage regulator. Also, p-n junction diodes are used in solar cells which is used to convert light energy into electrical energy. Light emitting diodes are also p-n junction diodes which are used to produce light. The digital circuit which gives the logical relationship between input and output voltage are called as logic gates. There are five basic gates namely NOT, AND, OR, NAND, NOR.

NOT gate is that logic gate which gives inverted input as output such as if 1 is the input given then output will be 0. The other logic gates OR, AND, NAND, NOR has two inputs and only one output.

(i) The semiconductors which are used to make visible LEDs must have band gap of ___

(ii)  Zener diode and photodiode works in the ____ bias mode.

(iii)  What is dynamic resistance?

 OR

 (iii)  What is barrier potential?