4 measureble properties of matter ae mass ,weight, volume , and pressure true or flase

Iknow the answer is a but i don't know why

The wave shown on the electromagnetic spectrum disturb the medium it passes through a)different frequency. b)the same frequency .

Adeuteron, 21h, is the nucleus of a hydrogen isotope and consists of one proton and one neutron. the plasma of deuterons in a nuclear fusion reactor must be heated to about 3.02×108 k . what is the rms speed of the deuterons? express your answer using two significant figures.