Units and Measurement
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Question : 12
Total: 33
The mass of a box measured by a grocer’s balance is 2.300 kg. Two gold pieces of masses 20.15 g and 20.17 g are added to the box. What is (a) the total mass of the box, (b) the difference in the masses of the pieces to correct significant figures?
Solution:
Here, mass of the box, m = 2.3 k g
Mass of one gold piece,m 1 = 20.15 g
= 0.02015 k g
Mass of other gold piece,m 2 = 20.17 g
= 0.02017 k g
(a) Total mass= m + m 1 + m 2
= 2.3 + 0.02015 + 0.02017
= 2.34032 k g
As the result is correct only upto one place of decimal, therefore, on rounding off total mass= 2.3 kg
(b) Difference in masses= m 2 − m 1
= 20.17 − 20.15
= 0.02 g
(correct upto two places of decimal).
Mass of one gold piece,
Mass of other gold piece,
(a) Total mass
As the result is correct only upto one place of decimal, therefore, on rounding off total mass
(b) Difference in masses
(correct upto two places of decimal).
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