Question

A metallic sphere cools from $50^{\circ} C$ to $40^{\circ} C$ in $300 \,s$ If atmospheric temperature around is $20^{\circ}\, C$, then the sphere's temperature after the next 5 minutes will be close to :

• A. $33^{\circ} C$
• B. $35^{\circ} C$
• C. $31^{\circ} C$
• D. $28^{\circ} C$

Answer 1

Answer: (A)

$\frac{50-40}{300}=\beta\left(\frac{50+40}{2}-20\right)$
$\frac{40- T }{300}=\beta\left(\frac{40+ T }{2}-20\right)$
$\therefore T =\frac{100}{3}$