Newton S Law Of Cooling — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Newton's Law of Cooling Valid for small temperature differences between the body and the surroundings, where cooling is primarily by convection or forced convection approximation. Assume rate of heat loss dQ/dt is proportional to temperature difference -(T - T s). Relate heat loss to temperature change via heat capacity: dQ = mc dT. Form differential equation: dT/dt = -k(T - T s). Integrate dT/(T - T s) = -k dt from 0 to t. Solve for T(t). Temperature difference (T - Ts) should be small relative to absolute temperature. k must be positive. T s is assumed constant. Believing the rate of cooling is constant (linear cooling) rather than exponential. Confusing the cooling constant k with thermal conductivity. Applying the law when the temperature difference is very large (Stefan-Boltzmann law dominates).