A body cools down from \(80^{\circ}\mathrm{C}\) $\mathrm{to}$ \(70^{\circ}\mathrm{C}\) in 5 minutes. The temperature of the same body will fall from \(70^{\circ}\mathrm{C}\)$\mathrm{}$ $\mathrm{to}$ \(60^{\circ}\mathrm{C}\)$\mathrm{}$ in:

Hot water cools from 60$°\mathrm{C}$ to 50$°\mathrm{C}$ in first 10 minutes and from 50$°\mathrm{C}$ to 42$°\mathrm{C}$ in next 10 minutes. The temperature of surrounding is :

1.  $5° \mathrm{C}$

2.  $10° \mathrm{C}$

3.  $15° \mathrm{C}$

4.  $20°\mathrm{C}$

A body cools from a temperature 3T to 2T in10 minutes. The room temperature is T. Assume that Newton's law of cooling is applicable. The temperature of the body at the end of next 10 minutes will be:
1. \(\frac{7}{4}T\)
2. \(\frac{3}{2}T\)
3. \(\frac{4}{3}T\)
4. \(T\)

A certain quantity of water cools from \(70^{\circ}\mathrm{C}\) to \(60^{\circ}\mathrm{C}\) in the first 5 minutes and to \(54^{\circ}\mathrm{C}\) in the next 5 minutes. 
The temperature of the surroundings will be: 

A bucket full of hot water cools from 75$°\mathrm{C}$ to 70$°\mathrm{C}$ in time ${\mathrm{T}}_1$, from 70$°\mathrm{C}$ to 65$°\mathrm{C}$ in time ${\mathrm{T}}_2$  and from 65$°\mathrm{C}$ to 60$°\mathrm{C}$ in time ${\mathrm{T}}_3$, then 
(1) ${\mathrm{T}}_1={\mathrm{T}}_2={\mathrm{T}}_3$              

(2) ${\mathrm{T}}_1>{\mathrm{T}}_2>{\mathrm{T}}_3$

(3) ${\mathrm{T}}_1<{\mathrm{T}}_2<{\mathrm{T}}_3$               

(4) ${\mathrm{T}}_1>{\mathrm{T}}_2<{\mathrm{T}}_3$