Fundamental Electrical Terms

Abstract

It is essential to understand the fundamental of electrical terms to comprehend any electrical phenomena. This chapter presents these necessary concepts and components as a first stepping stone in understanding any underlying electrical principles. In addition, it introduces the core measuring equipment in the electrical domain along with charge , current , voltage, power, energy, resistance, semiconductor and insulator.

Exercise Problems

• 1.1 A charge with an expression of $q = {\text{e}}^{ - 2t} + 6t^{2} + 3t + 2\;{\text{C}}$ is found in a circuit terminal. Determine the general expression of current and its vale at $t = 0.01\;{\text{s}}$.

• 1.2 A current of 6 A passes through a wire, where the expression of charge is found to be $q = {\text{e}}^{2t} + 3t\;{\text{C}}$. Calculate the value of the time.

• 1.3 A charge of 8 C moves through a wire for 2 s. Determine the value of the current.

• 1.4 A current as shown in Fig. 1.31 passes through a wire. Find the expressions of current for different times and the value of the charge.

  Fig. 1.31

  

  Current waveform with times

• 1.5 Fig. 1.32 shows a current waveform that passes through a wire. Calculate the expression of current and the value of the associated charge.

  Fig. 1.32

  

  Current waveform with times

• 1.6 The resistivity of a 200 m long and $1.04 \times 10^{ - 6} \;{\text{m}}^{2}$ copper wire is $1.72 \times 10^{ - 8} \;\Omega {\text{-m}}$. Calculate the value of the resistance.

• 1.7 The resistance of a copper wire is found to be 10 Ω. If the area and the resistivity of the wire are $0.95 \times 10^{ - 7} \;{\text{m}}^{2}$ and $1.72 \times 10^{ - 8} \;\Omega {\text{-m}}$, respectively, then find the length of the wire.

• 1.8 The resistivity of a 200 m long aluminium wire is $2.8 \times 10^{ - 8} \;\Omega {\text{-m}}$. Determine the diameter of the wire, if the resistance of the wire is 6 Ω.

• 1.9 A work with an expression of $w = 5q^{3} - 3q^{2} + q\;{\text{J}}$ is required to move a charge from one point to another point of a conductor. Calculate the voltage when $q = 0.01\;{\text{C}}$.

• 1.10 The work done for a time t s is given by $w = 2t^{2} + 10t\;{\text{J}}$. Find the value of the time for the corresponding power of 26 W.

• 1.11 A power $p = 2{\text{e}}^{ - 2t} + 5\;{\text{W}}$ is used for a time period 0.01 to 0.03 to complete a task. Calculate the corresponding energy.

• 1.12 A house uses twelve 40 W bulbs for 3 h, a 730 W iron for 1.5 h and a 40 W computer for 5 h. Calculate the total energy used in the house and the associated cost if the energy price is 10 cents per kWh.