Horium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years.

If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years?

Find the momentum for a 2.6-kg brick parachuting straight downward at a constant speed of 8.4 m/s .

In which situation has the independent variable for the experiment been changed? check all that apply. changed from counting the number of duckweed at day 0 and day 14 to counting them every day changed from testing duckweed growth in beakers to testing duckweed growth in large outdoor tanks changed from testing the effect of ph on duckweed growth to testing the effect of light levels on duckweed growth changed from testing the effect of acid ph on duckweed growth to testing the effect of basic ph on duckweed growth

The solar panels used by mark function because of the photoelectric effect. light shines on the cells causing electrons to be ejected from the metal, which produces an electric current. at night on mars, no light will fall on the solar cells and no electric current will be generated. according to your notes, what type of light is typically needed to cause the photoelectric effect? a)visible b)ultraviolet c)infrared