An electron is accelerated from rest through a potential difference of 70kV in a vacuum. Calculate the maximum speed acquired by the electron (electronic charge = -1.6 x 10-19; mass of an electron = 9.1 x 10-31kg)
When light from a source is sent through a gas
I. Certain wavelengths are absorbed.
II. an emission line spectrum results.
III. A dark line is left.
Which of the following is/are correct?
