as quoted from some guy on the ********** discord:
Recognise the distance travelled by the astronaut is 8 ly (0.8*10).
Recognise that light from Earth will therefore take 8 years to travel the distance to astronaut.
Therefore the light that he will see, will be the light from when he had been...
here is a link to howard's textbook for 4u, completely free
https://howardmathematics.com/wp-content/uploads/2021/12/HSC-Mathematics-Extension-2-Textbook-v9-2021-12-03.pdf
and here are 1000 4u questions also from steve howard...
but how come you used positive 1.602*10^-19 rather than -1.602*10^-19 for the charge of the electron
im sorry for sounding silly but i still dont rlly get the understanding behind it
just out of curiosity how would you have answered the original question if they didnt ask for electron volts and just wanted you to work in joules without making the conversion