Electric charges of `1mu C, -1 mu C` and `2mu C` are placed in air at the corners `A,B` and `C` respectively of an equilateral triangle `ABC` having length of each side `10 cm`. The resultant force on the charge at `C` is

Options

A. 0.9 N
B. 1.8 N
C. 2.7 N
D. 3.6 N

Answer

B

Explanation

r = 0.1m
`F_("net")=sqrt(F_(CA)^2 +F_(CB)^2+2F_(CA) .F_(CB)cos120)`
`=sqrt(F^2+F^2+2F^2(-1//2))=F`

`:. F=(Kq_Aq_c)/(r^2)=(9xx10^9xx1xx2xx10^(-12))/((0.1)^2)=1.8 N`