I need help with these questions.

I'll go ahead and answer the ones here without an answer. For reference, the half-life formula is final amount = original amount(1/2)^(time/half-life)

4) 12.5g

x = 100(1/2)^(63/21)

5) 50g

3.125 = x(1/2)^(0.1/0.025)

6) 500g

x = 4000(1/2)^(525/175)

7) 0.24g

0.06 = x(1/2)^(11430/5730)

8) 125g

x = 1000(1/2)^(17100/5700)

Hope this helps! :)

c)as speed changes, wavelength and frequency change.

everything changes!

answer: electrons