Question

A bucket full of hot water cools from 85 °C to 80 °C in time T₁, from 80 °C to 75 °C in time T₂ and from 75 °C to 70 °C in time T₃, then ______.

Options

• T₁=T₂=T₃

• T₁>T₂>T₃

• T₁<T₂<T₃

• T₁>T₂<T₃

Answer 1

A bucket full of hot water cools from 85 °C to 80 °C in time T₁, from 80 °C to 75 °C in time T₂ and from 75 °C to 70 °C in time T₃, then T₁<T₂<T₃.

Explanation:

According to Newton's law of cooling Rate of cooling ex: Mean temperature difference `⇒ "Fall in temperature"/"Time" α ((θ_1+θ_2)/2-θ_0)`

∴ `((θ_1+θ_2)/2)_1>((θ_1+θ_2)/2)_2>((θ_1+θ_2)/2)_3`

`⇒ "T"_1<"T"_2<"T"_3`