Question

Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of 4Ω in series with a combination of two resistors ( 8Ω each ) in parallel and a voltmeter across parallel combination. Each of them dissipate maximum energy and can withstand a maximum power of 16W without melting. Find the maximum current that can flow through the three resistors.

Answer 1

Hint
Use the formula of power. Components connected in series are connected along a single conductive path, so the same current flows through all of the components but voltage is dropped (lost) across each of the resistances. In a series circuit, the sum of the voltages consumed by each individual resistance is equal to the source voltage.

Complete step by step answer

According to the question in the circuit diagram thir is a cell indicated by the red circle, there is a key beside it. An ammeter indicated by A there is a resistor 4ohm in yellow circle, there is 2 resistor let 8 ohm each is in parallel and a voltmeter V across. The whole thing is connected in series with the 4 ohm resistor and the ammeter
Max current through 4 ohm resistor
$ \Rightarrow I = \sqrt {\dfrac{P}{R}} $
$ \Rightarrow I = \sqrt {\dfrac{{16}}{4}} = 2A$
Now, Max current through the each 8 ohm resistor= $\dfrac{1}{2} \times 2 = 1A$

Note
In this type of question the main thing is the diagram if you find out the proper diagram according to the question u can easily solve the other calculations. A parallel circuit has two or more paths for current to flow through. Voltage is the same across each component of the parallel circuit. The sum of the currents through each path is equal to the total current that flows from the source.