Question

The length and breadth of a field are measured as : `l = ( 120 +- 2) m and b = ( 100 +- 5) m` , respectively. What is the area of the field?

Answer 1

Now `(Delta A)/( A) = ( Delta l)/(l) + ( Delta b)/( b) = ((2)/(120) + (5)/(100)) = 0.0667,`
`Delta A = 0.0667 xx A `
Now `A = l . B = 120 xx 100 = 12000 m^(2)`
rArr `Delta A = 0.0667 xx 12000 = 800.4 m^(2)`
Area of the field `= A +- Delta A`
`= 12000 +- 800.4 = ( 1.2 +- 0.08) xx 10^(4) m^(2)`