Two friends are playing a version of proton golf where the hole is marked by a single proton. The first friend reads his meter, and declares he has a field strength of 24.0 N/C. The second friend looks at her meter and realizes she is three times as far away. What field strength does the second friend's meter read?

the electric field strength on the second one is 2.67 N/C.

Explanation:

the electric fiel on the first one is:

E1 = k*q / (r^2)

r^2 = k*q / (E1)

= (9*10^9) * (q) / (24.0)

= 375000000q

then the electric field on the second one is:

E2 = k*q / (R^2)

we know that R = 3r

R^2 = 9*r^2

E2 = k*q / (9*r^2)

= k*q / (9*375000000q)

= k / (9*375000000)

= (9*10^9) / (9*375000000)

= 2.67 N/C

Therefore, the electric field strength on the second one is 2.67 N/C.