Question

When the value of R in the balanced Wheatstone bridge, shown in the figure, is increased from 5 `Omega` to 7 `Omega`, the value of s has to be increased by 3 `Omega` in order to maintain the balance. What is the initial value of S?

Options

• 2.5 `Omega`

• 3 `Omega`

• 5 `Omega`

• 7.5 `Omega`

Answer 1

7.5 `Omega`

Explanation:

`"P"/"Q" ="R"/"S"`

Since P and Q is constant `"P"/"Q"` will be constant

`therefore "R"/"S"` = constant

`"R"/"S" = 5/"S" = 7/("S"+3`

`=> 5("S"+3)` = 7S

`therefore` 15 = 2S

`therefore "S" = 7.5 Omega `