Question

Which of the following is an example of convection?
A) The heat of the sun warming our planet
B) The heat from an electric stove warming a frying pan
C) Ice cubes cooling a drink
D) A microwave oven cooking a meal
E) An overhead fan cooling a room

Answer 1

Hint: There are three common methods to transfer heat from one to another which is conduction, convection and radiation. There is no major difference in that so we can answer the question with knowledge of heat transfer methods.

Complete step by step solution:
Heat transfer portrays the progression of warmth because of temperature contrasts and the resulting temperature circulation and changes. The exchange wonders concern the trading of force, energy, and mass as conduction, convection, and radiation.

Conduction is the cycle by which heat energy is sent through crashes between neighboring particles or atoms. Conduction happens all the more promptly in solids and fluids, where the particles are nearer together, than in gases, where particles are further separated. As per Fourier's Law which states that heat q resulting is straightforwardly relative to the greatness of the temperature inclination.
$q = - k\dfrac{{dT}}{{dx}}$
The constant, $k$ , is called the thermal conductivity
So, the warmth on a frying pan and the cooling activity of ice blocks are the two types of conduction.

Radiation is the wonder of transmission of energy starting with one body then onto the next proliferates through a medium. All bodies continually transmit energy by electromagnetic radiation. The force of such energy depends on the temperature of the body as well as on a superficial level attribute. The connection between energy, wavelength and frequency written as wavelength approaches the speed of light isolated by the frequency, or
$\lambda = cv$
Energy equivalents to Planck's steady occasions the frequency, or
$E = hv$
So, warmth of the sun and the cooking activity of a microwave are the two types of radiation.
Convection is the exchange of warmth because of the mass development of atoms inside liquid, including molten stone. Newton considered the convective cycle and give a straightforward equation for the cooling:
$\dfrac{{dT}}{{dt}} \propto T - {T_\infty }$
Where, ${T_\infty }$ is the temperature of the approaching liquid. This articulation recommends that energy is streaming ceaselessly from the body.
So, an overhead fan works by this technique: it sends cooler air particles down into a hot room, cooling the temperature of the room.

Note: Conduction, Convection and radiation all are methods for transfer of heat. You must know the precise difference between them before answering questions like these as these terms are confusing and you may end up getting the wrong answer. You may sometimes even need to memorize specific examples of each to make it easier for understanding.