One of the most efficient engines ever developed operated between 2100K and 700K. Its actual efficiency is 40%. What percentage of its maximum possible efficiency is this?

Explanation

Here, `T_(1)= 2100K`,
`T_(2)= 700K, eta_(actual)= 40%`
`eta_(max)= 1-(T_(2))/(T_(1))=1 -(700)/(2100)= 2/3`
`0.666= 66.6%`
`(eta_(actual))/(eta_(max))xx100= (40)/(66.6)xx100= 60%`