When two resistances R_1 and R_2 connected in series and introduced into the left gap of a meter bridge and a resistance of 10 Ω is introduced into…

When two resistances $\displaystyle R_1$ and $\displaystyle R_2$ connected in series and introduced into the left gap of a meter bridge and a resistance of $\displaystyle 10 \Omega$ is introduced into the right gap, a null point is found at $\displaystyle 60$ cm from left side. When $\displaystyle \mathrm{R}_1$ and $\displaystyle \mathrm{R}_2$ are connected in parallel and introduced into the left gap, a resistance of $\displaystyle 3 \Omega$ is introduced into the right-gap to get null point at $\displaystyle 40$ cm from left end. The product of $\displaystyle R_1 R_2$ is $\displaystyle \_\_\_\_$ $\displaystyle \Omega^2$