## Problem 1A.9 (7th edition)

$c=\lambda v$

Henry Krasner 1C
Posts: 64
Joined: Fri Sep 28, 2018 12:15 am

### Problem 1A.9 (7th edition)

In this problem, we are given one of the following options for four different scenarios: frequency, wavelength, and photon energy, and have to determine which option matches to which scenario, each of which is a different type of radiation.
Is it viable to just use the 2 formulas of c=λv and e=hv to calculate the data needed to complete the table and determine the sources?
Also, in c=λv, the correct unit for λ is meters, correct?

Minsub Lee 3E
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

### Re: Problem 1A.9 (7th edition)

Yes, use c=λv and e=hv to find the source. The correct unit for wavelength (λ) are meters.

Henri_de_Guzman_3L
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

### Re: Problem 1A.9 (7th edition)

Isn't it dumb how we need E=hv to solve this problem, yet that isn't given until 1B? Am I tripping?

Anusha 1H
Posts: 65
Joined: Fri Sep 28, 2018 12:15 am

### Re: Problem 1A.9 (7th edition)

Yea I thought that was strange too because 1A doesn't address Energy of the photon much apart from Table 1A.1

Diana Bibireata 1B
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

### Re: Problem 1A.9 (7th edition)

In the equation c=$\lambda \nu$ you do use meters (because the unit for c is meters per second)
But it is important to note that wavelengths in the visible spectrum are usually given in nanometers (which is 10-9m) so just also know this conversion.

Summer de Vera 2C
Posts: 65
Joined: Fri Sep 28, 2018 12:16 am

### Re: Problem 1A.9 (7th edition)

Yes, you can use both equations. You may also want to combine them for some, though I don't know if it's needed.