Answers by EE-Expert

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....

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)** |...

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**....

The storage battery of a car has an emf of 12V . If the internal resistance of the battery is 0.4 Ohm , what is the maximum current that can be drawn from the battery?
Answer : The maximum current that can be drawn from the battery is **30 Amperes (A)**. --- ### Detailed Explanation #### 1. Understand the Concepts * **EMF (Electromotive Force, $\mathcal{E ... even explode. This calculation is a theoretical maximum. **Never attempt to short-circuit a car battery.**...

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 |...

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.**...

A set of n-identical resistors, each of resistance R ohm when connected in series have an effective resistance of X ohm and when the resistors are connected in parallel the effective resistance is Y ohm. Find the relation between R , X and Y ?
Answer : Let's break this down step-by-step to find the relationship between R, X, and Y. ### 1. Resistors in Series When resistors are connected in series, their total effective resistance is the sum of ... the **geometric mean** of the total series resistance (X) and the total parallel resistance (Y)....

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....