There are two categories of ultraviolet light. Ultraviolet A ( UVA ) has a wavelength ranging from 320nm to 400nm . It is not so harmful to the skin and is necessary for the production of vitamin D. UVB, with a wavelength between 280nm and 320nm , is much more dangerous, because it causes skin cancer

PART A

Find the frequency ranges of UVA.

Enter your answers separated with commas.

fmin, fmax= 7.50

There are weak or strong attractive forces between atoms of liquids with a high viscosity

Who was the first scientist to measure speed as distance over time?

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.