Question

When two resistances 𝑅₁ and 𝑅₂ connected in series and introduced into the left gap of a meter bridge and a resistance of 10Ω is introduced into the right gap, a null point is found at 60 cm from left side. When 𝑅₁ and 𝑅₂ are connected in parallel and introduced into the left gap, a resistance of 3Ω is introduced into the right-gap to get null point at 40 cm from left end. The product of 𝑅₁𝑅₂ is _______ Ω².

Answer 1

Correct Answer: 30

Using the meter bridge principle: \[ \frac{R_1 + R_2}{10} = \frac{60}{40} \implies R_1 + R_2 = 15 \, \Omega. \] For the parallel combination: \[ \frac{R_1 R_2}{R_1 + R_2} = 3 \implies R_1 R_2 = 30 \, \Omega^2. \]