#### Question

Answer the following:

You are given a thread and a metre scale. How will you estimate the diameter of the thread?

#### Solution 1

Wrap the thread on a uniform smooth rod in such a way that the coils thus formed are very close to each other. Measure the length of the thread using a metre scale. The diameter of the thread is given by the relation,

Diameter = `"Length of thread"/"Number of turns"`

#### Solution 2

Wrap the thread a number of times on a round pencil so as to form a coil having its turns touching each other closely. Measure the length of this coil, mode by the thread, with a metre scale. If n be the number of turns of the coil and l be the length of the coil, then the length occupied by each single turn i.e., the thickness of the thread = 1/n. This is equal to the diameter of the thread