NEET Physics Newtons Law of Cooling MCQs Set 01

a) small excess of temperature over the surrounding

b) large excess of temperature over the surrounding

c) very large excess of temperature over the surrounding

d) any excess of temperature over the surrounding

Answer: small excess of temperature over the surrounding

Question:  A body cools in a surrounding of constant temperature 30°C. Its heat capacity is 2J/kg °C. Initial temperature of the body is 40°C. Assume Newton's law of cooling is valid. The body cools to 38°C in 10 minutes. In further 10 minutes it will cool from 38°C to

a) 36.4°C

b) 37°C

c) 37.5°C

d) 36°C

Answer: 36.4°C

Question: Rate of cooling of a spherical body is directly proportional to [where T = body temperature T₀ = surrounding temperature

a) (T – T₀)

b) T/T₀

c) T₀/T

d) None of these

Answer: (T – T₀)

Question: A body cools from 50.0°C to 49.9°C in 5s. How long will it take to cool from 40.0°C to 39.9°C? Assume the temperature of surroundings to be 30.0°C and Newton’s law of cooling to be valid

a) 10 s

b) 20 s

c) 5 s

d) 2.5 s

Answer:  10 s

Question:  In a room where the temperature is 30°C, a body cools from 61°C to 59°C in 4 minutes. The time (in minutes) taken by the body to cool from 51°C to 49°C will be

a) 6

b) 4

c) 5

d) 8

Answer: 6

Question: In a surrounding medium of temperature 10°C, a body takes 7 min for a fall of temperature from 60°C to 40°C. In what time the temperature of the body will fall from 40°C to 28°C?

a) 7 min

b) 11 min

c) 14 min

d) 21 min

Answer: 7 min

Question: A container contains hot water at 100°C. If in time T₁ temperature falls to 80° C and the time T₂ temperature falls to 60°C form 80°C, then

a) T₁ < T₂

b) T₁ = T₂

c) T₁ > T₂

d) None of these

Answer: T₁ < T₂

Question:  If a body cools down from 80°C to 60°C in 10 min when the temperature of the surrounding is 30°C, then the temperature of the body after next 10 min will be

a) 48°C

b) 50°C

c) 30°C

d) None of these

Answer:  48°C

Question:  A body cools from 50°C to 40°C in 5 minutes. The surrounding temperature is 20°C. In what further time (in minutes) will it cool to 30°C?

a) 25/3

b) 10

c) 15/2

d) 5

Answer:  25/3

Question:  Newton’s law of cooling is applicable for

a) None of these

b) large excess of temperature over the surrounding

c) very large excess of temperature over the surrounding

d) any excess of temperature over the surrounding

Answer:  None of these