What are the spectral type, temperature, absolute magnitude number, and luminosity of
Star A?

What produces light and all other electromagnetic waves? a) the photoelectric phenomena b) heated metals c) charged particles d) radioactive samples (pls explain if you can : )

Agas is contained in a vertical, frictionless piston–cylinder device. the piston has a mass of 3.2 kg and a cross-sectional area of 35 cm2. a compressed spring above the piston exerts a force of 190 n on the piston. if the atmospheric pressure is 95 kpa, determine the pressure inside the cylinder.

During takeoff, the sound intensity level of a jet engine is 170db at a distance of 34 m. what's the sound intensity level at a distance of 1.0 km?