Question

Virat is given the task of measuring a rigid curved steel rod as shown in the figure.
Which of the following objects should he use for getting the most accurate measurement?

• A. Only a metre scale
• B. A straight rod of known length
• C. Both a metre scale and a thread
• D. Only a thread

Answer 1

The correct option is C Both a metre scale and a thread

Virat cannot use a metre scale or a straight rod alone, as it cannot be bent along the curve. A thread and a metre scale can be used to measure the required length as shown in the diagram below. A thread is taken and aligned with the curved steel rod. The end points are marked on the thread. Next, the length of the thread between the marked points is measured by a metre scale after straightening it.