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Question
Find the effective resistance in the following circuit diagrams (Fig.):

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Solution

The situation consists of three 10 ohm resistors connected in series between CEFD and their combination in parallel with the fourth 10 ohm resistor between C and D.
Therefore, series combination gives, 10 + 10 + 10 = 30Ω .
This 30Ω resistor is connected in paral le I to the fourth 10 O resistor, therefore equivalent resistance between C and D,
Therefore, series combination gives, 10 + 10 + 10 = 30Ω
This 30Ω resistor is connected in paral le I to the fourth 10 Ω resistor, therefore equivalent resistance between C and D,
`1/"R" = 1/10 + 1/30 = 4/30 Ω`
R = 7.5Ω
Now, between A and B the resistance Rand two 10Ω resistors are connected in series.
Therefore, equivalent resistance between A and B is
`"R"_"total" = 10 + 10 + 7.5 = 27.5 Ω`
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