Hot questions

A high tension (HT) supply of, say, 6 kV must have a very large internal resistance. Why?
Answer : The primary reason is **safety and current limiting**. Let's use Ohm's Law ($V = IR$) to understand this. A power supply can be modeled as an ideal voltage source ($V_s$) in series ... HT supply for **power transmission** has a very low internal resistance for **efficiency and power delivery**....

Explain the uses of safety rubber hand gloves and rubber mats in electrical engineering.
Answer : In electrical engineering, safety is paramount. Two of the most fundamental and critical pieces of Personal Protective Equipment (PPE) are **safety rubber hand gloves** and **insulating rubber ... environment and preventing a worker's body from becoming the path of least resistance for electricity....

Explain the use of following tools in carrying out electrical wiring installation: (i) Nose pliers (ii) Test lamps (iii) Crimping tools (iv) Cutter.
Answer : General Introduction In electrical wiring, using the correct tool for the job is not just about efficiency; it is a fundamental requirement for safety and the quality of the finished installation. A poor ... Do not use them to cut steel wire or screws, as this will damage the cutting edges....

Explain the reasons for failure of gaseous and solid dielectric materials used in electrical engineering application.
Answer : ### **Introduction to Dielectric Failure** A dielectric material is an electrical insulator that can be polarized by an applied electric field. Its primary function in electrical engineering is to ... Often a slow, aging-related process - Highly sensitive to impurities, voids, and moisture |...

Explain the use of the following components in electrical wiring system and give specification of each: (i) MCB (ii) ELCB
Answer : ### Introduction In any modern electrical wiring system, safety and protection are paramount. Devices like MCBs and ELCBs are critical safety components installed in a consumer unit (also known as a ... (lighting, sockets, etc.) | Protecting a group of circuits or an entire installation |...

A cylindrical wire is stretched to increase its length by 10% calculate the percentage increase in resistance?
Answer : The percentage increase in resistance is **21%**. Here is the step-by-step calculation and explanation: ### The Key Concepts 1. **Resistance Formula:** The resistance (R) of a wire is given by: $R = \ ... R_1}{R_1} \times 100\%$ $\text{Percentage Increase} = 0.21 \times 100\% = \bf{21\%}$...

Obtain ohm’s law from the expression for electrical conductivity.
Answer : We can derive the familiar form of Ohm's Law ($V=IR$) by starting with the fundamental expression for electrical conductivity ($\sigma$). This derivation beautifully connects the microscopic behavior of ... total **current ($I$)** flowing through it, successfully obtaining Ohm's Law, $V=IR$....

Define emf. of a cell? On what factors does it depend?
Answer : ### Definition of EMF (Electromotive Force) The **EMF (Electromotive Force)** of a cell is defined as the maximum potential difference between its two terminals when no current is being drawn ... *, not its EMF. A larger distance increases the path ions must travel, increasing internal resistance....

Two wires A and B are of the same metal and of same length have their areas of cross section in the ratio 2:1 if the same potential difference is applied across each wire in turn, what will be the ratio of current flowing in A & B ?
Answer : The ratio of the current flowing in wire A to wire B is **2:1**. --- ### Detailed Explanation Let's break down the problem using the relevant physics principles. #### 1. List the Given ... resistance, which is wire A. Our result confirms this: the current in A is twice the current in B....

Three identical cells, each of emf. 2V and unknown internal resistance are connected in parallel. This combination is connected to a 5 ohm resistor. If the terminal voltage across the cell is 1.5 volt. What is the internal resistance of each cell? Hence define the internal resistance of a cell?
Answer : ### Part 1: Calculating the Internal Resistance Here's how we can find the internal resistance of each cell. **Given Data:** * Electromotive force (EMF) of each cell, E = 2 V * Number of identical cells ... . * **I** is the current flowing from the cell. * **r** is the internal resistance....