Experimental Physics

JEE Main level, single correct, medium

43 of 70

Question 43 of 70

A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings 5.50mm5.50mm, 5.55mm5.55mm, 5.34mm5.34mm, 5.65mm5.65mm. The average of these four reading is 5.5375mm5.5375mm and the standard deviation of the data is 0.07395mm0.07395mm. The average diameter of the pencil should therefore be recorded as :

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Answer: (D) (5.54±0.07)mm\left(5.54\pm 0.07\right)mm

Significant rule says that reading should has same significant figure as that of reading given.
5.5375→5.5375\rightarrow rounded to →5.54.\rightarrow 5.54.
0.07395→\rightarrow rounded to→\rightarrow0.07
therefore, (5.54±0.07)mm\left(5.54\pm 0.07\right)mm

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