Significant Figures

As explained in NCERT Class 11, Chapter 2 (Units and Measurements), significant figures represent the digits in a measurement that are known reliably plus the first uncertain digit. The rules state that all non-zero digits are significant, and zeros lying between two non-zero digits are also significant regardless of the decimal point. In the value 7.203 m, the digits 7, 2, 0 and 3 are all counted; the zero is sandwiched between 2 and 3 so it is significant. This gives a total of four significant figures. The option 3 is wrong because it incorrectly discards the embedded zero. The option 5 is wrong since there is no fifth digit in the number. The option 2 is wrong because it ignores three clearly recorded digits. A final check shows that the precision implied by four significant figures matches a millimetre-level tape reading, which is physically reasonable for a metre-scale wire.