## connexus.com Group Title Ok so on this what do I do (Please don't give me the answer I just want to know what I need to do on it) Medical X-rays, with a wavelength of about 10^-10m, can penetrate completely through your skin. Ultraviolet rays, which cause sun burn by penetrating only the top level of skin, have a wavelength about 1000 times the wavelength of an X-ray. find the wavelength of ultraviolet rays. Show your work. 11 months ago 11 months ago

1. terenzreignz Group Title

It seems too simple, but, you just do what the problem says, and, it seems it *explicitly* says '1000 times the...' which would normally indicate that you multiply by a factor of 1000.

2. connexus.com Group Title

So I multiply 10^-10 by 1000?

3. terenzreignz Group Title

I would think so.

4. connexus.com Group Title

So its 100,000,000,000,000?

5. terenzreignz Group Title

Okay, so, what do you think $\Large 10^{-10}$means?

6. connexus.com Group Title

I did 10^-10 * 1000 and got 100,000,000,000,000

7. terenzreignz Group Title

How? Why? lol

8. connexus.com Group Title

Well I asked if I multiply 10^-10 * 1000 and you said you think so :P

9. terenzreignz Group Title

Yes, that's true, but how exactly did you arrive at your answer? $\Large \left.\begin{matrix}10^{-10}\cdot 1000&=&100 \ 000 \ 000 \ 000 \ 000\\&\color{red}?&\end{matrix}\right.$

10. connexus.com Group Title

First I multiplied out 10^-10 and got 100,000,000,000 then I multiplied it by 1000 and got 100,000,000,000,000

11. terenzreignz Group Title

Hang on, why is $\Large 10^{-10}$equal to 100 000 000 000

12. connexus.com Group Title

I multiplied it out

13. connexus.com Group Title

...

14. connexus.com Group Title

Am I not suppose to do that...

15. klimenkov Group Title

What is $$a^{-1}$$ ?

16. terenzreignz Group Title

Sorry... the problem here is that the exponent was negative... so it's not as straightforward as simply 'multiplying out'

17. terenzreignz Group Title

But first, @klimenkov asked you a question ^_^

18. connexus.com Group Title

|dw:1377670025131:dw|

19. terenzreignz Group Title

Okay, now what about $\Large a^{-n}$

20. connexus.com Group Title

|dw:1377670107287:dw|

21. connexus.com Group Title

Now can we get back to the question sorry for the rush I just have a ton of work I have to get done tonight

22. terenzreignz Group Title

Okay... well, if you could do that with the 'a' What is $\Large 10^{-10}$ ?

23. klimenkov Group Title

Now, what is $$10^{-10}$$ ?

24. connexus.com Group Title

|dw:1377670300729:dw|

25. connexus.com Group Title

Was not thinking I have had so much going on today with school

26. terenzreignz Group Title

That's right :) Now multiply THAT to 1000. And let me take the liberty of reminding you that $\Large 1000 = 10^3$

27. connexus.com Group Title

Ok so it equals 10^7

28. terenzreignz Group Title

No... it's the bottom exponent that's bigger...

29. terenzreignz Group Title

$\Large 10^{-10}\cdot 10^3$ First law of exponents... when you multiply, with same base, ADD the exponents.

30. connexus.com Group Title

That's what I was doing...|dw:1377674852025:dw|

31. terenzreignz Group Title

Yes. That's right :D $\Large \frac1{10^7}=10^{-7}$

32. connexus.com Group Title

Thanks :)

33. connexus.com Group Title

Can you please help me on this one to? the wavelengths of visible light are between 3.8 * 10^-7m and 7.6 * 10^-7m. Are these wavelengths longer or shorter than those of ultraviolet rays? Explain On it do I need to simplify each scientific notation out and just put how I simplified them and put what one is bigger?