A positron and an electron annihilate each other upon colliding, thereby producing energy in the form of two gamma rays. Assuming that both gamma rays have the same energy (since both particles have the same mass), calculate the wavelength of the electromagnetic radiation used in pm. (1 pm = 10⁻¹² m; mass of electron (amu) = 0.000549)

Which of the following statements are true of solids? a. the particles do not vibrate. b. the particles are in a fixed location. c. they have strong intermolecular forces between the atoms or molecules. d. the particles have less kinetic energy than those of liquids or gases.

Assume that a person skiing high in the mountains at an altitude of h = 15100 ft takes in the same volume of air with each breath as she does while walking at sea level. determine the ratio of the mass of oxygen inhaled for each breath at this high altitude compared to that at sea level. assume that the air composition (i. e. % of air that is oxygen) is the same at sea level as it is at 15100 ft.

For waves in the ocean, the medium of the waves is a. air b. water c. energy d. a passing boat