Electromagnetic radiation with a wavelength of 525 nm appears as green light to the human eye. The energy of one photon of this light is j.

3.784 * 10^(-9) J

Explanation:

Wavelength of the light, λ = 525 nm = 525 * 10^(-9) m

The energy of a wave is given in terms of wavelength as:

E = hc/λ

Where h = Planck's constant

c = speed of light

Therefore, Energy, E, is:

E = (6.626 * 10^(-34) * 2.998 * 10^8) / (525 * 10^(-9))

E = 3.784 * 10^(-9) J

This is the energy of the wave and hence, a photon.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.