Physicists speculate that, early in its history, the universe shifted from a "false vacuum" state to a "true vacuum" state. what is the significance of this transition?

An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

What are similarities and differences between refraction, reflection, diffraction and absorption?

The charge on an electron is 1.60218 × 10−19 c and its mass is 9.10939 × 10−31 kg. how strong a magnetic field must be experienced by the electron if its path is a circle of radius 5.5 cm? answer in units of t.