Ta có: HB= HC= HA = \(\frac{a\sqrt{2}}{2}\Rightarrow E_{AH}=E_{BH}=\frac{kq}{\left(\frac{a\sqrt{2}}{2}\right)^2}=\frac{2kq}{a^2}\), EHC=\(\frac{2kq}{r^2}=\frac{2kq}{\left(\frac{a\sqrt{2}}{2}\right)^2}=\frac{4kq}{a^2}\)
Ta có:
E'=EHC-EHB= \(\frac{2kq}{a^2}\Rightarrow E_H=\sqrt{E'^2+E^2_{HA}}=\frac{2\sqrt{2}kq}{a^2}=\frac{18\sqrt{2}.10^9.q}{a^2}\)
tham khảo:
Vật lí - Vật lí 11 | Cộng đồng học sinh Việt Nam - HOCMAI Forum