What is the main factor that prevents the growth of tropical plants in the northern part of the united states

Two polarizers are oriented at 70∘∘ to one another. unpolarized light falls on them. what fraction of the light intensity is transmitted?

You are given two vectors a⃗ =−3.00ι^ 5.00j^ and b⃗ =5.00ι^ 2.00j^. let the counterclockwise angles be positive.

Which basic property determines a colored light's placement on the spectrum of visible light? a. speed b. frequency c. amplitude d. velocity