The transfer of energy by heat flow through a substance is accomplished by conduction convection radiation all of the above

conduction

Explanation: There are three modes of heat transfer

1. Conduction: This type of heat transfer happens when there is direct contact between the two object.

2.  Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas).

3.  Radiation: This type of heat transfer happens when there is direct transfer of energy through space.

The transmission of heat by the transferring of energy from one particle to another happens in conduction when two bodies are in direct contact with one another.

v = 8.4 m/s

Explanation:

The question ays, "A longitudinal wave has a frequency of 200 Hz and a wavelength of 4.2m. What is the speed of the wave?".

Frequency of a wave, f = 200 Hz

Wavelength = 4.2 cm = 0.042 m

We need to find the speed of the wave. The formula for the speed of a wave is given by :

So, the speed of the wave is equal to 8.4 m/s.