## speed of light

$c=\lambda v$

emily gao 1C
Posts: 61
Joined: Fri Sep 28, 2018 12:29 am

### speed of light

When we do hw, should we use 3.0x10^8 m/s for the speed of light, or a more accurate value?

Moryel Yashar 1J
Posts: 31
Joined: Fri Sep 28, 2018 12:15 am

### Re: speed of light

The exact speed of light is 299,792,458 m/s, but for our purposes, 3.0x10^8 m/s is perfectly fine as well.

mayra martinez 1D
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Joined: Fri Sep 28, 2018 12:17 am

### Re: speed of light

In the solutions manual they recommend using 2.998x10^8 m/s for the speed of light but if you round up then yea you could use 3x10^8

Amy Dinh 1A
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Joined: Fri Sep 28, 2018 12:23 am

### Re: speed of light

You can use 3.00 x 10^8 m/s, but you could use 2.998 x 10^8 or 2.99792 x 10^8 (in Lavelle's constants and equations sheet).

Sana_Mian_3G
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Joined: Fri Sep 28, 2018 12:23 am

### Re: speed of light

I think in lecture he said that the speed of light in a vacuum is 3.0x10^8 m/s, but I would probably go off the "Constants and Equations" worksheet on the website.

Sam Kelly 1K
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Joined: Fri Sep 28, 2018 12:16 am

### Re: speed of light

Sort of unrelated, but since we are working solely with the speed of light in a vacuum, I'm wondering what the speed of light is when not in a vacuum (if that even makes sense?)

Raj_Bains_2C
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### Re: speed of light

I don't think that it matters on the homework problems if we use 3.0 x 10^8 m/s or a more precise value, but for the tests, I would stick to using the value that is on the constants and equations sheet.

Lydia Luong 4L
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Joined: Fri Sep 28, 2018 12:24 am

### Re: speed of light

I think 3.0 x 10^8 is fine!

Chem_Mod
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### Re: speed of light

In response to Sam's question, the speed of light in another medium (not a vacuum) is slower than the measured value of 30 million m/s. The actual number depends on the specific medium we are talking about. For example, the speed of light in water is about 3/4 the speed of light in a vacuum.