Question
Write Newton's law of cooling and explain the necessary condition for it and also explain the cooling curve.
✓
Answer
Newton's law of cooling : According to Newton's law of cooling, if the heat excess is less than the surrounding environment, then the net energy emitted per second by the object or rate of cooling of the object is proporitonal to the heat excess. This law was propounded by Newton through experiment.
Necessary conditions : (1) The value temperature difference of the object and the surroundings should be less than the absolute temperature of the surroundings i.e. $\text T_0 = \text {Absolute temperature of surrounding}$
(2) Heat loss from the object should be only through radiation.
(3) This law is obtained from Stefan, Boltzmann law which applies for black-body so the radiating surface should be black.
Cooling curve : The graph between the temperature of the body and time is called cooling curve. The gradient of the tangent at any point on the curve gives the rate of temperature.
Necessary conditions : (1) The value temperature difference of the object and the surroundings should be less than the absolute temperature of the surroundings i.e. $\text T_0 = \text {Absolute temperature of surrounding}$
(2) Heat loss from the object should be only through radiation.
(3) This law is obtained from Stefan, Boltzmann law which applies for black-body so the radiating surface should be black.
Cooling curve : The graph between the temperature of the body and time is called cooling curve. The gradient of the tangent at any point on the curve gives the rate of temperature.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A simple pendulum performs S.H.M. about x = 0 with an amplitude a and time period T. What is the speed of the pendulum at $\text{x}=\frac{\text{A}}{2}?$
→There is glycerine in one container and water in the other container. Both are Shaken vigorously and placed on the table. The liquid in which container will come to rest first and why?
If velocity of sound in a gas depends on its elasticity and density, derive the relation for the velocity of sound in a medium by the method of dimensions.
Between a flat plate of $100 sq . cm$ area a bigger plate is a layer of 1 mm thick glycerine. If the coefficient of viscosity of glycerine is $1.0 kg / m$ sec then how much force is required to move the plate with a velocity of $7 cm / sec$ ?
→Write Avogadro's law
Explain the difference between weight and mass.
The changes in a function y and the independent dy variable x are related as $\frac{\text{dy}}{\text{dx}}=\text{x}^2.$ Find y as a function of x.
→The position-time (x-t) graphs for two children A and B returning from their school O to their homes P and Q respectively are shown in Fig. Choose the correct entries in the brackets below :
(a) (A/B) lives closer to the school than (B/A)
(b) (A/B) starts from the school earlier than (B/A)
(c) (A/B) walks faster than (B/A)
(d) A and B reach home at the (same/different) time
(e) (A/B) overtakes (B/A) on the road (once/twice).
(a) (A/B) lives closer to the school than (B/A)
(b) (A/B) starts from the school earlier than (B/A)
(c) (A/B) walks faster than (B/A)
(d) A and B reach home at the (same/different) time
(e) (A/B) overtakes (B/A) on the road (once/twice).
Two masses M and m are connected at the two ends of an inextensible, light string. The string passes over a smooth frictionless pulley. Calculate the acceleration of the masses and the tension in the string. M is heavier than m.
Explain why:
The climate of a harbour town is more temperate than that of a town in a desert at the same latitude.
The climate of a harbour town is more temperate than that of a town in a desert at the same latitude.