Why do scientist use radioactive decay to figure out how old stuff is

What is the molecular mass of magnesium chloride, MgCl2? (how do you get to the answer as well)

Red light from three separate sources passes through a diffraction grating with 6.60*105 slits/m. The wavelengths of the three lines are 6.56 * 10-7m (hydrogen), 6.50 * 10-7m (neon), and 6.97 * 10-7m (argon).

Severe weather often includes destructive events such as Hurricanes and Tornadoes where air is moving much faster than usual. True or False

What is 550cm in meters. Show the work

Given a die, would it be more likely to get a single 6 in six rolls, at least two 6s in twelve rolls, or at least one-hundred 6s in six-hundred rolls?

About how much energy is transferred between a producer and primary consumer? A. 90% of the original energy from the Sun is transferred B. 10% of the original energy from the Sun is transferred C. 10% of the plant's energy is transferred D. 0.

If you exert a force of 500 n to walk 4 m up a flight of stairs in 4 s, how much power do you use?

The concepts of a "particle" and a "wave"

If a particle undergoes shm with amplitude 0.10 m, what is the total distance it travels in one period?

If the length of one side of a square is 12.0 m, what is the perimeter of the square?