Recent questions without an upvoted answer

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**....

A battery of emf E and internal resistance r sends a current, I1 , I2 when connected to an external resistance of R1 , R2 respectively. Find the emf. and internal resistance of the battery.
Answer : Let's derive the expressions for the electromotive force (EMF) and the internal resistance of the battery step-by-step. ### Understanding the Setup The core principle we'll use is Ohm's law applied to the entire circuit. For a ... $$ **EMF (E):** $$ E = \frac{I_1 I_2 (R_1 - R_2)}{I_2 - I_1} $$...

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**....

State and explain Kirchhoff’s law?
Answer : Kirchhoff's laws are two fundamental principles used to analyze electric circuits. They were formulated by Gustav Kirchhoff in 1845 and are based on the conservation of charge ... =blob&qa_blobid=16131873694589351449 [2]: https://electrical-engineering.app/?qa=blob&qa_blobid=10917265924274549047...

Explain with the help of a circuit diagram, how the value of an unknown resistance can be determined using a Wheatstone bridge?
Answer : ![][1] [1]: https://electrical-engineering.app/?qa=blob&qa_blobid=407323477172242274 ### **Introduction** A Wheatstone bridge is an electrical circuit used for the precise measurement of an ... (R₃) at the balance point has been recorded, the unknown resistance Rₓ can be calculated precisely....

What is drift velocity? Derive expression for drift velocity of electrons in a good conductor in terms of relaxation time of electrons?
Answer : --- ### Part 1: What is Drift Velocity? In a metallic conductor (like a copper wire), the outer electrons of the atoms are not bound to individual atoms. They are free to move throughout the entire volume of ... field. * The magnitude of the drift velocity is given by: $v_d = \frac{e\tau}{m}E$....

With suitable circuit diagram, show how emfs of 2 cells can be compared using a potentiometer?
Answer : ![][1] [1]: https://electrical-engineering.app/?qa=blob&qa_blobid=16022041933233000659 ### **Principle of a Potentiometer** A potentiometer works on the principle that the potential drop ... -section. 4. The current in the primary circuit should be kept constant throughout the experiment....

Why do we prefer a potentiometer to measure the emf of a cell rather than a voltmeter?
Answer : The primary reason we prefer a potentiometer to measure the EMF of a cell is that **a potentiometer draws no current from the cell at the point of measurement.** A voltmeter, by its ... method ensures no current is drawn, thereby eliminating any error caused by the source's internal resistance....