A) Sunlight basically consists of a combination of light of different wavelengths. Each of these wavelengths correspond to each of the colors of the rainbow. For example, red light has the longest wavelength. This is followed by orange, then yellow, green, blue and indigo. Violet has the shortest wavelength. These wavelengths (750 nm to 400 nm) constitute the visible colors. All these light components of different wavelengths combine together to become the color white.
b) When this sunlight passes through droplets of rain, it gets refracted and that is what breaks up the white light into individual colors of the rainbow, just how light passing through a glass prism gets broken down into its individual seven colors.
c) Different objects have the ability to absorb different wavelengths of light. For example, glass absorbs light of all wavelengths except those between 560-520nm, which corresponds to green light. So it reflects the green light and thus, our eyes see grass as green in color.
d) Light of wavelength below 400 nm (ultraviolet) and above 750nm (Infrared) are not visible. However, they exist in the sun's radiation. Ultraviolet rays are very harmful and responsible for causing sunburn and some types of skin tumors. Infrared light is also harmful and can cause premature wrinkling of skin.
We have that there is a formula connecting these three. V=I*R where V is voltage, I is the current and R is the resistance. Substituting, we get that V=210 Volta, which is the unit of measurement for voltage. You can think of the relationship in the following way : The energy of the field is equal to the flow of the field times the resistance that it meets.
The answer to your question is "A. a lower frequency of the siren.
Because the person in back of the ambulance will hear a lower frequency of the siren. This is because the waves are stretched out. A longer wavelength results in a lower frequency.
