Q 12-03-299NEETNEET 2022Top questionMedium
A wheatstone bridge is used to determine the value of unknown resistance $X$ by adjusting the variable resistance $Y$ as shown in the figure. For the most precise measurement of $X$, the resistances $P$ and $Q$
Answer: (C) Should be approximately equal and are small
A Wheatstone bridge is most sensitive when all four arms have resistances of the same order. Then a small change in $Y$ near balance gives the largest galvanometer deflection, so the balance point is found most precisely.
So $P$ and $Q$ should be about equal to each other (and comparable to $X$, i.e. not very large). Of the given choices, "approximately equal and small" is the right one.
Solution by Sreeraj P, M.Sc Physics