Recent questions without an upvoted answer

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....

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....

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 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....

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....