## 7th Edition #1.3

$E=hv$

Linyu Zeng 1H
Posts: 28
Joined: Fri Sep 28, 2018 12:19 am

### 7th Edition #1.3

I have a question about rounding my answer. The result I get without any rounding in the calculation process is 753W. But the answer on the book is 750. I don't understand why this difference happens. Should I round 753 to 750?

Camille Marangi 2E
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: 7th Edition #1.3

It is most likely a matter of sig figs. One of the givens is 2.4 x 10^21 photons and that only has 2 sig figs so that means the problem's answer will have 2 sig figs (750 as zero in the last digit of a whole number is not a sig fig).