Question
Question: Electric charges of \(1\mu C, - 1\mu C\) and \(2\mu C\) are placed in air at the corners A, B and C ...
Electric charges of 1μC,−1μC and 2μC 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
A
0.9 N
B
1.8 N
C
2.7 N
D
3.6 N
Answer
1.8 N
Explanation
Solution
FA = force on C due to charge placed at A
=9×109×(10×10−2)210−6×2×10−6=1.8N
FB = force on C due to charge placed at B
=9×109×(0.1)210−6×2×10−6=1.8N

Net force on C
Fnet=(FA)2+(FB)2+2FAFBcos120o=1.8N