Four resistors have values R₁ = R₂ = R₃ = 5 Ω and R₄ = 10 Ω. Which circuit shown in the original figure gives an equivalent resistance of 6 Ω?
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Question

Four resistors have values R₁ = R₂ = R₃ = 5 Ω and R₄ = 10 Ω. Which circuit shown in the original figure gives an equivalent resistance of 6 Ω?

G1 Physics · Accepted Answer

In option 1, R₁ and R₂ are in series, giving R t o p R_top R t ​ o p = 5+5 = 10 Ω. R₃ and R₄ are also in series, giving R b o t t o m R_bottom R b ​ o tt o m = 5+10 = 15 Ω. These two branches are in parallel: R e q R_eq R e ​ q = (10×15)/(10+15) = 150/25 = 6 Ω. Therefore option 1 gives the required equivalent resistance. Correct option: A.