Question

The equivalent resistance between A and B is ____________.

Options

• 3 ohms

• 5.5 ohms

• 7.5 ohms

• 9.5 ohms

Answer 1

The equivalent resistance between A and B is 7.5 ohms.

Explanation:

Redrawing the circuit, we get

3 `Omega` & 6 `Omega` are in parallel.

`"R"_1 = (3 xx 6)/(3 + 6) = 18/9 = 2  Omega`

Now `"R"_1  "and"  8  Omega` in series

`therefore "R"_2 = "R"_1 + 8 = 2 + 8 = 10  Omega`

Now `"R"_2  "and"  30  Omega` in parallel

Rep = `("R"_2 xx 30)/("R"_2 + 30) = (10 xx 30)/(10 + 30)`

`= 300/40 = 30/4 = 15/2`

`= 7.5  Omega` (iii) correct option