Hot questions

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} $$...

In a potentiometer arrangement, a cell of emf 1.25V gives a balance point at 35.0cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 63.0cm , what is the emf of the second cell?
Answer : ### Principle The working principle of a potentiometer is that the potential drop across any portion of a wire of uniform cross-section is directly proportional to the length of that portion, provided a constant current flows ... 2.25 V** ### Answer The EMF of the second cell is **2.25 V**....

A Carbon resistor has three strips of red colour and a gold strip. What is the value of the resistor? What is its tolerance?
Answer : The value of a carbon resistor is determined by the standard resistor color code system. For a 4-band resistor: * **Band 1:** First significant digit * **Band 2:** Second significant ... a new resistor with these color bands will have an actual resistance somewhere between 2090 Ω and 2310 Ω....

State the procedure for laying / installation of underground cable.
Answer : 1) Direct laying Cable: or Trench laying method: ![][1] [1]: https://electrical-engineering.app/?qa=blob&qa_blobid=2239248645105787017 Procedure:  For laying of a cable trench about 1.5m deep ... one cable does not damage the adjacent cable.  Only armored cables are used in this method. ...

State one condition for maximum current to be drawn from the cell?
Answer : For maximum current to be drawn from a cell, the **external resistance in the circuit should be zero**. This condition is also known as a **short circuit**. **Explanation:** The current (I) drawn from a cell ... possible value is 0. When R = 0, the current is at its maximum value, I_max = E / r....

What are ohmic and non-ohmic resistors? Give one example of each?
Answer : **Ohm's Law** states that the voltage ($V$) across a conductor is directly proportional to the current ($I$) flowing through it, provided all physical conditions and temperature remain constant. Mathematically, ... | **Carbon Resistor**, Nichrome Wire | **Filament Light Bulb**, Diode, Thermistor |...

If the temperature of a good conductor decreases, how does the relaxation time of electrons in the conductor change?
Answer : ### The Short Answer If the temperature of a good conductor decreases, the **relaxation time of electrons increases**. --- ### The Detailed Explanation To understand why, let's break ... **. This is why good conductors become even better conductors (less resistive) at lower temperatures....

What happens to the resistance of the wire when its length is increased to twice its original length?
Answer : This gets to the core of how resistance works. The short and direct answer is: **The resistance of the wire will double.** Here's a more detailed explanation of why. ### 1. The Simple Explanation (Analogy) Think of the wire ... (x2) | Halves (x0.5) | **Quadruples (x4)** |...

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: $v_d = \frac{e\tau}{m}E$....

If potential difference V applied across a conductor is increased to 2V , how will the drift velocity of the electron change?
Answer : ### Short Answer If the potential difference V applied across a conductor is increased to 2V, the **drift velocity of the electrons will also double**. ### Detailed Explanation Let's ... the electric field, which doubles the force on the electrons, which doubles their average drift velocity....