Two substances `A` and `B` of equal mass m are heated by uniform rate of `6 "cal"s^(-1)` under similar conditions. A graph between temperature and time is shown in figure. Ratio of heat absorbed `H_(A) //H_(B)` by them during complete fusion :-

Options

A. `9/4`
B. `4/9`
C. `24/5`
D. `5/8`

Answer

C

Explanation

From given curve,
Melting point for A = `60^(@)`C
And melting point for B = `20^(@)`C
Time taken by A for fusion = (6-2) = 4min
Time taken by B for fustion = (6.5 -4) = 2.5 min
Then `(H_(A)/H_(B))` = `(6xx4xx60)/(6 xx 2.5 xx20)=24/5`