Newton's Law of Cooling — Practice Quiz

Question 1

A body cools from 80°C to 60°C in 5 min in 20°C surroundings. Time to cool from 60°C to 40°C:

Accepted Answer

Greater than 5 min

Answer

5 min

Answer

Less than 5 min

Answer

Cannot determine

Question 2

Newton's law of cooling assumes:

Accepted Answer

Small ΔT (linear regime)

Answer

Large ΔT

Answer

Vacuum

Answer

Solid surroundings

Question 3

A cooling curve fits T(t) = 25 + 75·e^(−0.1t) (in min). Initial T:

Accepted Answer

100°C

Answer

25°C

Answer

75°C

Answer

200°C

Question 4

Faster cooling for the same body occurs when:

Accepted Answer

Surface area increases or T_s decreases

Answer

Surface area decreases

Answer

Body is heavier

Answer

T_s = T

Question 5

Cooling curve eventually approaches:

Accepted Answer

T_s (surroundings)

Answer

Zero

Answer

T_0 (initial)

Answer

Infinity