At some time (t = 0) mas of a Radon (Rn) [atomic number 86 and atomic mass number 222] sample is 0.38 µg. Half-life of Radon is 3.8235 days. Avogadro’s number = 6.02 x 1023. (a) Determine the initial number of nuclei in the sample
(b) Determine the initial activity of the sample
(c) Determine the number of nuclei present in the sample after 5.0 h

An architect plans to use solar energy to heat the next house he designs. what principle of absorption and infrared energy can be applied to the design of the new house? how could she apply to those principals?

The lid of a pressure cooker forms a nearly airtight seal. steam builds up pressure and increases temperature within the pressure cooker so that food cooks faster than it does in an ordinary pot. the system is defined as the pressure cooker and the water and steam within it. if 2.0 g of water is sealed in a pressure cooker and then vaporized by heating, and 5655 j must be added as heat to completely vaporize the water, what is the change in the system’s internal energy? answer in units of j.

Explain how waste energy is produced when an inefficient lightbulb converts electrical energy into radiant energy.