Recent questions in Physics

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....

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....

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, $V=IR$....

Find the value of unknown resistance X in the circuit shown in the figure if no current flows through the section AO. Also calculate the current drawn by the circuit from the battery of emf. 6V ... resistance. ![][1] [1]: https://electrical-engineering.app/?qa=blob&qa_blobid=394010198424626099
Answer : ### Part 1: Finding the value of the unknown resistance X The problem states that no current flows through the section AO. Let's label the central junction point as 'O'. 1. **Identify the Principle:** The ... resistance **X is 6Ω**. * The current drawn by the circuit from the battery is **1A**....