Why is si system better than CGS system

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 : )

What is the difference between electrically neutral objects and electrically charged objects

6–55 refrigerant-134a enters the condenser of a residential heat pump at 800 kpa and 358c at a rate of 0.018 kg/s and leaves at 800 kpa as a saturated liquid. if the compressor consumes 1.2 kw of power, determine (a) the cop of the heat pump and (b) the rate of heat absorption from the outside air.