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### Speed of light constant

Posted: Sun Apr 15, 2018 11:21 pm
When reviewing the properties of light Dr. Lavelle gave as the constant c as 3.00 x 10ˆ8 m/s. I understand that this constant will always be given and that it is part of a formula but I was quite confused as to which type of problem/when would we use this constant?

### Re: Speed of light constant

Posted: Sun Apr 15, 2018 11:27 pm
this is the speed of light in a vacuum so this constant is wavelength x frequency

### Re: Speed of light constant

Posted: Sun Apr 15, 2018 11:27 pm
You will see this constant in the wave equations f=c/λ which relates wavelength and frequency. If given frequency of an electromagnetic wave and asked to find the wavelength, then you would use the speed of light constant.

### Re: Speed of light constant

Posted: Mon Apr 16, 2018 12:38 am
Do we need to memorize the speed of light in different conditions for the exam?

### Re: Speed of light constant

Posted: Mon Apr 16, 2018 9:13 am
Taizha 1C wrote:Do we need to memorize the speed of light in different conditions for the exam?

I believe that such constants will be given to us on the exam.

### Re: Speed of light constant

Posted: Wed Apr 18, 2018 9:10 pm
The speed of light constant, c, will be provided to us as previously mentioned and can be used in a variety of problems. We recently have also begun to conduct calculations using E= h x v as well as En= (-h x R)/(n^2). These questions often give us energy levels that electrons transition from and require us to find wavelength. Since the equation c=wavelength x frequency is needed for wavelength, we would need to use c in these types of problems as well.