| ⇦ | 
| ⇨ |
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: - In one dimensionsal motion,instantaneous speed v statisfies 0⦤v⦤vₒ
- Radii of curvature of a converging lens are in the rato 1:2. Its focal length
- When the temperature increases, the viscocity of
- A hollow metal sphere of radius 10 cm is charged such that the potential on its surface
- When a radioactive substance emits an ∝ particle, its position in the periodic table
Topics: Properties of Bulk Matter
(130)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- In one dimensionsal motion,instantaneous speed v statisfies 0⦤v⦤vₒ
- Radii of curvature of a converging lens are in the rato 1:2. Its focal length
- When the temperature increases, the viscocity of
- A hollow metal sphere of radius 10 cm is charged such that the potential on its surface
- When a radioactive substance emits an ∝ particle, its position in the periodic table
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