Coulomb's law

1. Nov 19, 2013

Tony Tesla

Hi, Can someone help me with this question? I understand Coulomb's law but i want to know if I am doing it right.
So the charge of
Q1= 2 mC
Q2= 1 mC
And R= 5 cm (0,05m)
This is how i solved it.
F= K(8,988x10^9) x (2x10^-6)x(1x10^-6) / (0,05m)^2
F= K(8,988x10^9) x 8x10^-10
F= 7.1904 N

2. Nov 19, 2013

Tanya Sharma

Hi Tony Tesla...

Welcome to PF!!

1mC = 10-3C , not 10-6C

3. Nov 19, 2013

Tony Tesla

Submultiples Multiples
Value Symbol Name Value Symbol Name
10−1 C dC decicoulomb 101 C daC decacoulomb
10−2 C cC centicoulomb 102 C hC hectocoulomb
10−3 C mC millicoulomb 103 C kC kilocoulomb
10−6 C µC microcoulomb 106 C MC megacoulomb
10−9 C nC nanocoulomb 109 C GC gigacoulomb
10−12 C pC picocoulomb 1012 C TC teracoulomb
10−15 C fC femtocoulomb 1015 C PC petacoulomb
10−18 C aC attocoulomb 1018 C EC exacoulomb
10−21 C zC zeptocoulomb 1021 C ZC zettacoulomb
10−24 C yC yoctocoulomb 1024 C YC yottacoulomb
Common multiples are in bold face.

Source: http://en.wikipedia.org/wiki/Coulomb

I think it is 10^-6

Now i see it i typed Mc instead of μC
Sorry

4. Nov 19, 2013

Tony Tesla

I see now, I ment μC not mC sorry.

5. Nov 19, 2013

Tanya Sharma

Even then your calculations are wrong.

Recheck...

6. Nov 19, 2013

Tony Tesla

checked it 5 timed every time the answer was 7.1904 N
and the answer there was also 7.1904 N

7. Nov 19, 2013

ehild

The solution for the force is correct if the charges are given in μC .

ehild

8. Nov 19, 2013

Tony Tesla

Thank you

9. Nov 19, 2013