```Heat Transfer                                        Perfect Blackbody
  It is the exchange of thermal energy                 It absorbs all light/radiation in its reach.
between physical systems.                             According to basic laws of physics, the
  The rate of heat transfer is dependent on             more energy a body absorbs the more it
the temperatures of the systems and the               can emit. Therefore, a black body absorbs
properties of the intervening medium                  all energy directed at it and also emits all
through which the heat is transferred.                energy that"s been absorbed.
  The three fundamental modes of heat                  However, if heated to a high temperature,
transfer are conduction, convection and               a blackbody will begin to glow with
radiation.                                            thermal radiation.
   The energy emitted by a blackbody is
Conduction                                               called blackbody radiation.
  An energy transfer across a system                Newton"s Law of Cooling
boundary due to a temperature difference
by the mechanism of intermolecular                   It states that the rate of change of the
interactions.                                         temperature of an object is proportional to
  It needs matter and does not require any              the difference between its own
bulk motion of matter.                                temperature and the ambient temperature
  Snow is a poor conductor and so keeps the             (i.e. the temperature of its surroundings).
earth warm.                                          T(t) = Ts + (T0 – Ts) e(-kt)
  e.g. Using a heating blanket to get warm.            T(t) = temperature of an object at a certain
time (Kelvin, K)
Convection                                              t = time (s)
  An energy transfer across a system                   Ts = temperature of the surroundings
boundary due to a temperature difference              (Kelvin, K)
by the combined mechanisms of                        T0 = starting temperature of the object
intermolecular interactions and bulk                  (Kelvin, K)
transport.                                           k = a cooling constant, specific to the
  It needs fluid matter.                                object (1/s)
  e.g. Putting your wet shoes on a floor vent       Kirchhoff"s Law of Thermal Radiation
to dry them faster.
   It states that wavelength-specific radiative
Radiation                                                emission and absorption by a material
  It involves the transfer of heat by                   body in thermodynamic equilibrium,
including radiative exchange equilibrium.
electromagnetic radiation that arises due to
the temperature of the body. It does not             It signifies that good absorbers are good
need matter.                                          emitter.
  e.g. A person placing their cold hands over          If a shining metal ball with some black
a warm fire.                                          spot on its surface is heated to a high
  Advection – It is the transfer of energy              temperature the shining ball becomes dull
from one location to another as a side                but the black spots shines brightly because
effect of physically moving an object                 black spot absorbs radiation during
containing that energy.                               heating and emit in dark.
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