Question

The temperature of a body falls from ${50}^{\circ }C$ to ${40}^{\circ }C$ in $10$ minutes. If the temperature of the surroundings is ${20}^{\circ }C$ Then the temperature of the body after another $10$ minutes will be

• A. ${36.6}^{\circ }C$
• B. ${33.3}^{\circ }C$
• C. ${35}^{\circ }C$
• D. ${30}^{\circ }C$

Answer 1

The correct option is B ${33.3}^{\circ }C$

In first case $\frac{50-40}{10}=K[\frac{50+40}{2}-20]$

In second case $\frac{40-{\theta }_2}{10}=K[\frac{40+{\theta }_2}{2}-20]$

By solving ${\theta }_2={33.3}^{\circ }C$