Which of the following is the best explanation of why it is difficult to discriminate the color of an object at night?

a. cones come in three types, each sensitive to different wavelengths of light.
b. the foveae are densely packed with cones.
c. at night, the amount of light entering the eye is insufficient to stimulate the cone cells but is sufficient to stimulate the rod cells.
d. as many as 100 cones may converge on one ganglion cell.

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

If you put a helium-filled balloon in the refrigerator, what will happen?

See the attachment and solve question 5th