What are three methods of heat transfer and what are some examples

I am studying heat transfer and have learned there are three kinds of heat transfer: conduction, convection, and radiation. Some examples are:

Conduction:

Touching a stove and being burned

Ice cooling down your hand

Boiling water by thrusting a red-hot piece of iron into it

Convection:

Hot air rising, cooling, and falling (convection currents)

An old-fashioned radiator (creates a convection cell in a room by emitting warm air at the top and drawing in cool air at the bottom).

Radiation:

Heat from the sun warming your face

Heat from a lightbulb

Heat from a fire

Heat from anything else which is warmer than its surroundings.

Explanation: A good example would be heating a tin can of water using a Bunsen burner. Initially the flame produces radiation which heats the tin can. The tin can then transfers heat to the water through conduction. The hot water then rises to the top, in the convection process.

The atmosphere would be another example. The atmosphere is heated by radiation from the Sun, the atmosphere exhibits convection as hot air near the equator rises producing winds, and finally there is conduction between air molecules, and small amounts of air-land conduction.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg