# Tricky but interesting circuit problem ?

Find the voltage across terminals a and b, Vab

A) V/5

A) 4V/5

A) 2V/3

A) 3V/2

A) other

### 3 Answers

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- Anonymous2 months ago
2R is by-passed

Req = 4R // 4R = 2R

Vab = V*Req/(Req+R) = V*2/(2+1) = 2V/3

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- Dr. ZorroLv 72 months ago
Without thinking, I would say answer A) is correct ;-)

RealPro gave the full analyses. The trick is to spot the short circuited resistor (2R).

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- RealProLv 72 months ago
You ignore the 2R resistor because the current bypasses it through the leftmost wire. Resistance between A and B is (R+3R=4R) parallel to 4R which is 2R in total.

The resistance of the whole circuit is 3R.

2/3 of the circuit resistance is between A and B so 2V/3.

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