The question is incomplete. The complete question is :
A platypus foraging for prey can detect an electric field as small as 0.002 N/C.
-To give an idea of sensitivity of the platypus's electric sense, how far from a +80nC point charge does the field have this magnitude?
Solution :
Given electric field, E = 0.002 N/C
Charge, Q = + 80 nC
![$\therefore E = (kQ)/(R^2) $](https://img.qammunity.org/2022/formulas/physics/college/cndacelumua9zr6ivf6yf4htpuyswsmp5n.png)
or
![$R^2=(kQ)/(E)$](https://img.qammunity.org/2022/formulas/physics/college/ne6pu78mror6wrq0dco4k1yf3lpyyiegyd.png)
![$R^2=(9* 10^9 * 80 * 10^(-9))/(0.002)$](https://img.qammunity.org/2022/formulas/physics/college/3i9wrjof984rsdpcalk1d50a5fjiiqygzq.png)
R = 600 m
This is the distance of the charge from the point of observations.