Radius of a Raindrop given Charge and Electric Potential

[freddy13]

Homework Statement

A spherical rain drop carries a charge of 5×10-6 C and has a potential of 8.800×10-8 V at the surface. Find the radius of the drop.

Homework Equations

V = (kQ)/r

The Attempt at a Solution

I simply moved V and r to their respective spots and plugged in my numbers. I got a very large number of 5.11*10^11, so i am wondering if my units are wrong or if I am doing something else wrong. Thanks for your help!

 

[TSny]

Hello, freddy13.

You're right, you're getting a ridiculous answer even though your method is correct. (Your answer for the radius is more than 3 times the distance to the sun.) The value for the potential looks very suspicious. Are you sure that 10 is raised to the negative 8 power? Also, the value for the charge seems very high for a raindrop.

 

[freddy13]

Yeah I copied the problem exactly! It has to be something with the units that I am missing, that seems to be the only possibility!

 

[TSny]

I agree. It must be a misprint in the statement of the problem.