The measurement of an unknown resistance R is to be carried out using a Wheatstone bridge. Two students perform an experiment in two ways. The first students take ${\mathrm{R}}_2$ = 10 $\mathrm{\Omega }$ and ${\mathrm{R}}_1$ =5 $\mathrm{\Omega }$. The other student takes ${\mathrm{R}}_2$ =1000 $\mathrm{\Omega }$ and ${\mathrm{R}}_1$ =500 $\mathrm{\Omega }$. In the standard arm, both take ${\mathrm{R}}_3$ = 5 $\mathrm{\Omega .}$

Both find $\mathrm{R}=\frac{{\mathrm{R}}_2}{{\mathrm{R}}_1}{\mathrm{R}}_3=\mathrm{10 }\mathrm{\Omega }$ within errors.

(a) The errors of measurement of the two students are the same.

(b) Errors of measurement do depend on the accuracy with which ${\mathrm{R}}_2$ and ${\mathrm{R}}_1$ can be measured.

(c) If the student uses large values of ${\mathrm{R}}_2$ and ${\mathrm{R}}_1$, the currents through the arms will be feeble. This will make the determination of the null point accurately more difficult.

(d) Wheatstone bridge is a very accurate instrument and has no errors of
measurement.

1. (a, c)

2. (c, d)

3. (b, c)

4. (c, d)