Q. 42

# Find the current

Answer :

Concepts/Formula used:

Resistors in Series:

Resistors in parallel:

Potential Difference (V) across a resistor of resistance R when current I passes through it is given by Ohm’s law:

Let the current through the ammeter be . We can see that the upper and lower part are completely identical. So , there is no reason they should have different currents. Hence, the current equally distributes into each branch due to symmetry.

Due to this symmetry, d and h; e and i are the same potential. Hence, no current passes through *de* and *ei*.

Hence, we can redraw the circuit by removing the resistors across *dh* and *ei*.

We can see that the resistors across *cd*, *de* and *ef* are in series. Hence,

Similarly,

We can rewrite the circuit as follows:

We can easily see that *cf* and *gj* are in parallel.

Now, the circuit looks like this:

By Ohm’s law,

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