## 6th Edition Ch1.33B

$E=hv$

Imelda Mena 3I
Posts: 51
Joined: Thu Oct 02, 2014 3:00 am

### 6th Edition Ch1.33B

Hey, can someone explain why (2.5x10^16 1/s) is used as the velocity and not the velocity that was given at the beginning of the problem (3.6x10^3 km/s)? Thank you in advance!

Andrea Zheng 1H
Posts: 61
Joined: Fri Sep 28, 2018 12:26 am

### Re: 6th Edition Ch1.33B

In part (b), they are asking for the energy that is needed to remove the electron. This means that you would use the equation E=h*frequency. This is why the solution uses the value (2.5x10^16 1/s), as this is the value that is given for frequency. Because you already know h (Planck's constant), you can solve for the energy. You would not need the velocity for part (b).