Radius of a wire is 2.50 mm. The length of the wire is 50.0 cm. If mass of wire was measured as 25g, then find the density of wire in correct significant figures.
`[Given, pi = 3.14, exact]`

Answer

B, C

Explanation

Given , r = 2.50 mm
= 0.250cm
Further given that,
` l = 50.0 cm `
m = 25gm
`pi = 3.14 exact `
`rho = m/V = m/(pi r^2 l)`
`= (25)/((3.14)(0.250)(0.250)(50.0))`
`= 2.5477 g//cm^3`
But in the measured values, least number of significant figures are two. Hence, we will round off the result to two significant figures.
`:. rho = 2.5 g//cm^(3)`