The relative density of material of a body is found by weighting it first in air and then in water . If the weight in air is `( 5.00 +- 0.05) N` and the weight in water is `(4.00 +- 0.05) N`. Find the relative density along with the maximum permissible percentage error.

Options

A. `(5.00 + 0.05)`
B. `5.00 +- 11%`
C. `5.00 +- 0.10`
D. `5.00 +- 6%`

Answer

(b)

Explanation

Relative density `rho = ("weight in air")/("loss of weight in water")`
`= (W_a)/(W_a - W_w)`
`rho = (5.00)/(1.00) = 5.00`
`(Delta rho)/(rho) = (Delta W_a)/(W_a) + (DeltaW_a+Delta W_w)/(W_a - W_w)`
`(d rho)/(rho) = (0.05)/(5.00) + (0.1)/(1.00) = 0.11 = 11%`
`:. rho = 5.00 +- 11%`