If the laser is pointed toward a pinhole with a diameter of 1.0 mm, how many photons will travel through the pinhole per second? Assume that the light intensity is equally distributed throughout the entire cross-sectional area of the beam. (1 W = 1j/s )? An argon ion laser puts out 4.4 W of continuous power at a wavelength of 532 nm. The diameter of the laser beam is 6.0 mm.

Achemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. an example of a chemical reaction is the formation of water from hydrogen and oxygen gas.in a physical change, a substance changes its physical appearance but not its chemical identity. an example of physical change is the formation of liquid water from solid water, a familiar process called melting. physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? oxygen gas changes to ozone during thunderstorms carbon dioxide is produced by the combustion of gasoline in an automobile engine. when coal, oil, and natural gas are decomposed in landsills they produce methane gas. freezing rain develops when a warm air mass overrides a cold air mass. fog forms from water vapor when the temperature drops below the dew point

Drug abuse will not lead to physical and psychological dependence. true or false ?

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it