KVPY Sample Paper KVPY Stream-SX Model Paper-27

A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair?

A) 0.035 mm

B) 2 mm

C) 0.5 mm

D) 1.5 mm

Correct Answer: A

Solution :

Magnification of microscope = 100

Observed width of the hair = 3.5 mm

Estimated on the thickness of hair is given by Magnification\[=\frac{oberved\,width}{Real\,widrth}\]

Or Real width \[=\frac{oberved\,width\,}{Magnification}=\frac{3.5}{100}=0.035mm\]