Electric field strength of van de graff generator

[thisischris]

A VDGG is used to produce a large PD. The dome of the generator has a radios of 0.15m. It is charged and gets a PD between the dome and the Earth of 75kV.

The charged stored on it is : 5.0 x 10^-6C

Answer: Use of E = Q/4∏εr₀. 3.0 x 10⁵

My attempt: E = kQ/r² = 8.99 x 10⁹ x 5.0 x 10^-6 / 0.15² = 2.00 x 10⁶

I get the provided answer if I don't square the 0.15. It also seems to be a potential print error as r is not squared in their equation as well as having a 0 as a sub-ponent(opposite of exponent?)... Could anyone share any light on this?

Much appreciated :)

 

[dipole]

Uh what is the question?

 

[thisischris]

Sorry, long day!

I get an answer of 2.0 x10⁶, while the provided answer is 3.0 x 10⁵.