Question

what physical principle is involved during working of chimneys of lamps and furnance​

Answer 1

Solution :

See the attachment for a labelled diagram of the circuit .

Here , we can clearly see that CE , EF , and FD are in series .

Equivalent resistance between them : 10 Ω + 20Ω + 20Ω = 50 Ω .

Now CD and the previous equivalent resistance are in parallel .

New Equivalent Resistance = 50×30/(50+30) = 1500/80 = 150/8 = 185 Ω .

This 185 Ω is parallel with the other two 10 Ω resistors .

Thus the final equivalent resistance becomes 205 Ω.

Answer - The equivalent resistance is 205 Ω .

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