What is the speed of a wave that has a wavelength of 20 cm and a period of 0.5 s? 4 cm/s 40 cm/s 0.025 cm/s 10 cm/s

Positrons are spontaneously emitted from the nuclei of

What conclusion can be made based on the temperature of soil when the light hits the soil at 0°, 45°, and 90° angles in section 2 of the experiment? did your results support your hypothesis? why or why not?

Which system of units is used by only a small number of countries in the world, including the u.s.