Maximum Potential and Charge of Generator

[123yt]

Homework Statement

A Van de Graaff generator is used to demonstrate the effects of high potential. The device has a radius of 86.0 cm and stands in air. What is its maximum potential? (Note: An electric field of 3 × 106 Vm is sufficiently large to cause sparking in air.)

How much charge does the dome hold at its maximum potential?

Homework Equations

Electric Potential = (1/4*pi*e0) * q / r

The Attempt at a Solution

I already found the maximum potential to be 2.58 * 10^6 V.

For the charge: I substituted 2.58 * 10^6 V into the equation along with the radius.

2.58 * 10^6 V * 4 * pi * e0 * 0.86 m = q
q = 0.000247 C

This wasn't the correct answer.

 

[zorro]

I too got the same answer. The answer given might be wrong. What's it anyways?

 

[123yt]

I don't know yet. I have about 3 more tries left.

I entered the answer as 0.00025. Could the problem be with my significant figures?

EDIT: Nope, significant figures aren't the problem. 2 tries left.

 

[zorro]

lol... where are you trying them?
Try to answer in scientific notation.

 

[123yt]

I did. It still won't work. I probably got the completely wrong answer.

 

[zorro]

Your answer is right according to me. I have no idea why it is showing wrong.