The wavelength of light visible to the human eye is on the order of 4 x 10-7 m.
Find the frequency of the lightwave if the
speed of light in air is 2.99792 x 108 m/s.
Answer in units of s-1.

What are igneous intrusions and extrusions

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

Afisherman notices that his boat is moving up and down periodically, owing to waves on the surface of the water. it takes a time of 2.70 s for the boat to travel from its highest point to its lowest, a total distance of 0.700 m. the fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart. a. how fast are the waves traveling? b. what is the amplitude a of each wave?