This diagram represents a p-n junction diode - NSC Technical Sciences - Question 7 - 2020 - Paper 1

The symbol for a p-n junction diode consists of a triangle pointing towards a line. The triangle represents the p-type material, while the line represents the n-type material. Here is a representation:

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An intrinsic semiconductor, such as silicon or germanium, has four valence electrons. This allows it to form covalent bonds with neighboring atoms.

A capacitor is an electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material called a dielectric. When voltage is applied across the plates, an electric charge is stored, creating an electric field between them.

The relationship between capacitance (C) and charge (Q) on the plates of a capacitor is given by the formula:

$Q = C imes V$

where Q is the charge, C is the capacitance, and V is the voltage across the plates.

1. Decrease the surface area of the plates: Reducing the area of the conductive plates will lower the capacitance.

2. Increase the distance between the plates: Increasing the separation distance will also decrease the capacitance.

First, calculate the power consumed by the lamp using the formula:

$P = I^2 imes R = (2 ext{ A})^2 imes 60 ext{ Ω} = 240 ext{ W} = 0.24 ext{ kW}$

Next, calculate the electricity consumed in two hours:

$ext{Energy} = P imes t = 0.24 ext{ kW} imes 2 ext{ h} = 0.48 ext{ kWh}$

Finally, calculate the cost:

$ext{Cost} = ext{Energy} imes ext{tariff} = 0.48 ext{ kWh} imes R1.75 = R0.84$