The radius of a sphere is measured to be `(2.1 +- 0.02) cm`. Calculate its surface area with error limits.

Answer

`55.4 +- 26.4 cm^(2)`

Explanation

`r = 2.1 +- 0.5 cm`
rArr `A = 4 pi r^(2) = 4 xx (22)/(7) (2.1)^(2)`
`= 4 xx 13.86 = 55.4 cm^(2)`
`( Delta A)/( A) = 2( Delta r )/( r ) rArr Delta A = ( 2 xx 0.5)/(2.1) xx 55.44 = 26.4`
Area ` = 55.4 +- 26.4 cm^(2)`