Question: Q. 2. (i) In the following diagram, which bulb out of $B_{1}$ and $B_{2}$ will glow and why?
(ii) Draw a diagram of an illuminated $p-n$ junction solar cell.
(iii) Explain briefly the three processes due to which generation of emf takes place in a solar cell.
U [O.D. II 2017]
Show Answer
Solution:
Ans. (i) Identification of the bulb and reason $1 / 2+1 / 2$
(ii) Diagram of solar cell $1 / 2+1 / 2+1 / 2$
(iii) Names of the processes
(i) Bulb $B_{1}$ glows
Diode $D_{1}$ is forward biased
(ii) Diagram :
(iii) Generation : Incident light generates electronhole pairs.
Separation : Electric field of the depletion layer separates the electrons and holes.
Collection : Electrons and holes are collected at the $n$ and $p$ side contacts.
[CBSE Marking Scheme, 2017]
Commonly Made Error
- Some common errors made by students are :
(i) A.C. input voltages at A & B are not shown.
(ii) Complete circuit was not drawn.
(iii) Resistor in o/p circuit $\left(R_{L}\right)$ was not shown
(iv) The circuit was not labelled.
