Hot questions

A low voltage supply from which one needs high currents must have very low internal resistance. Why?
Answer : ### The Simple Analogy: A Water Pipe Imagine your power supply is a large water tank (representing the voltage) and you need to get a high flow of water (high current) out of a pipe at ... extremely small, this will generate a massive amount of heat, which can damage or destroy the power supply....

State the properties of copper and aluminium which make them good conductors of electricity.
Answer : ### 1. Presence of Delocalized Valence Electrons This is the most fundamental reason. * **What it is:** In metallic bonding, the outermost electrons (valence electrons) of the ... density and lower cost make it a vital material for specific applications like long-distance power transmission....

Name any one material having a small value of temperature coefficient of resistance. Write one use of this material?
Answer : **Material:** **Manganin** (an alloy of copper, manganese, and nickel) **Use:** Due to its very low temperature coefficient of resistance, it is used to make ** ... for electrical measuring instruments like ammeters and Wheatstone bridges, where a stable and predictable resistance is essential....

Two electric bulbs A and B are marked 220V , 40W and 220V 60W respectively. Which one has a higher resistance?
Answer : **The 40W bulb (Bulb A) has a higher resistance.** Here's the detailed explanation of why: ### The Relationship The relationship between Power (P), Voltage (V), and Resistance (R) is given by ... to get more water through a pipe; you need a wider pipe (less resistance) to increase the flow rate....

Two heated wires of the same dimensions are first connected in series and then it’s parallel to a source of supply. What will be the ratio of heat produced in the two cases?
Answer : Here is the step-by-step solution: ### The Short Answer The ratio of heat produced in the series case to the parallel case is **1:4**. --- ### Detailed ... proportional to this current, the parallel circuit draws significantly more power and therefore produces significantly more heat....

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, $V=IR$....

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....

Why is constantan or manganin used for making standard resistors?
Answer : Constantan and manganin are used for making standard resistors for a specific combination of four key properties that make them ideal for precision applications. Here's a breakdown of why these alloys ... precision and stability required in a metrology lab, **manganin is the preferred material.**...

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**....

State why the resistance of the conductor increases with the rise in temperature.
Answer : Here is a clear explanation of why the resistance of a conductor increases with a rise in temperature, broken down into a simple analogy and the underlying physics. --- ### Simple Analogy: The ... More collisions** mean more opposition to the flow, which is, by definition, **higher resistance**....