Answer:

Explanation:
The energy difference between the energy levels involved in the transition of the electron is directly proportional to the frequency of the emitted photon:

Where h is the Planck constant. The photon's frequency is inversely proportional to its wavelegth:

Here c is the speed of light. Replacing (2) in (1):

Answer:
A. The sound wave will reflect off Buildings and automobiles.
Explanation:
This is because the sound waves would more likely propagate through diffraction through buildings and transmission through the air. It is also more likely to be absorbed by buildings than for multiple reflections to occur off buildings and automobiles. In the process of reflection, these materials would absorb the sound energy thereby reducing its ability to reflect.
It comes from the sun, and then it is converted to energy/electricity (by solar panels)
The third one sliding friction
Explanation:
Answer:
Fluids exert forces on objects because of many molecules of the fluid that continuously collide with the surfaces of the object immersed in the fluid. ... A steel boat floats on water but a steel block does not because the block has more weight than the steel boat due to the buoyant force.
Explanation: