Which statement is true about an atom and an element?
a) an atom can be broken down into different substances and an element is formed when two or more atoms combine.
b) an atom is made of identical elements and an element retains all of the characteristics of a particular atom.
c)an atom is the smallest unit of matter and an element is a pure substance that is made of identical atoms.

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?

How to calculate voltage drop in a series circuit