| ⇦ | 
| ⇨ |
Certain quantity of water cools from 70⁰ C to 60⁰C in the first 5 minutes and to 54⁰ C in the next 5 minutes. The temperature of the surroundings is
Options
(a) 45⁰ C
(b) 20⁰ C
(c) 42⁰ C
(d) 10⁰ C
Correct Answer:
45⁰ C
Explanation:
Let the temperature of surroundings be θ₀
By Newton’s law of cooling
(θ₁ – θ₂ / t) = k [(θ₁ – θ₂ / 2) – θ₀]
[(70 – 60) / 5] = k [(70 + 60 / 2) – θ₀] ⇒ 2 = k [65 – θ₀] ——(i)
Similarly, (60 – 54) / 5 = k = [(60 + 54 / 2) – θ₀]
6 / 5 = k [57 – θ₀] ——–(ii)
By dividing (i) by (ii) we have
10 / 6 = (65 – θ₀) / (57 – θ₀) ⇒ θ₀ = 45⁰
Related Questions: - A boy playing on the roof of a 10m high building throws a ball with a speed
- The average power dissipated in a pure inductor is
- The ratio of the acceleration for a solid sphere(mass m and radius R)rolling down
- A person wants a real image of his own, 3 times enlarged. Where should he stand
- The wave function (in SI unit) for a light wave is given as Ψ(x,t)= 10³ sin π
Topics: Properties of Bulk Matter
(130)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A boy playing on the roof of a 10m high building throws a ball with a speed
- The average power dissipated in a pure inductor is
- The ratio of the acceleration for a solid sphere(mass m and radius R)rolling down
- A person wants a real image of his own, 3 times enlarged. Where should he stand
- The wave function (in SI unit) for a light wave is given as Ψ(x,t)= 10³ sin π
Topics: Properties of Bulk Matter (130)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
18000+ students are using NEETLab to improve their score. What about you?
Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.
Share this page with your friends
Leave a Reply