Step 1: Understanding Solar Cell Materials A solar cell (photovoltaic cell) converts sunlight into electricity through the photovoltaic effect. The efficiency and performance of solar cells depend on the material used.
Step 2: Why Silicon? - Silicon (Si) is the most commonly used material in solar cells due to:
- Abundance: Readily available and cost-effective.
- Semiconductor Properties: Ideal for electron flow under sunlight.
- High Efficiency: Monocrystalline and polycrystalline silicon provide high energy conversion rates.
Step 3: Evaluating options:
- (A) Incorrect: Germanium is a semiconductor but less efficient than silicon in solar applications.
- (B) Correct: Silicon is the standard material for solar cells.
- (C) Incorrect: Silica gel is used for moisture absorption, not in photovoltaic cells.
- (D) Incorrect: Mercury is not used in solar cell fabrication.
A continuous time periodic signal \( x(t) \) is given by: \[ x(t) = 1 + 2\cos(2\pi t) + 2\cos(4\pi t) + 2\cos(6\pi t) \] If \( T \) is the period of \( x(t) \), then evaluate: \[ \frac{1}{T} \int_0^T |x(t)|^2 \, dt \quad {(round off to the nearest integer).} \]
The Nyquist plot of a strictly stable \( G(s) \), having the numerator polynomial as \( (s - 3) \), encircles the critical point \(-1\) once in the anti-clockwise direction. Which one of the following statements on the closed-loop system shown in the figure is correct?

The open-loop transfer function of the system shown in the figure is: \[ G(s) = \frac{K s (s + 2)}{(s + 5)(s + 7)} \] For \( K \geq 0 \), which of the following real axis point(s) is/are on the root locus?

If A + B means A is the mother of B; A - B means A is the brother of B; A % B means A is the father of B, and A \(\times\) B means A is the sister of B, which of the following shows that P is the maternal uncle of Q?