Electrostatics Question 449
Question: Two point charges $ +9e $ and $ +e $ are at 16 cm away from each other. Where should another charge q be placed between them so that the system remains in equilibrium [MP PET 2002]
Options:
A) 24 cm from $ +9e $
B) 12 cm from $ +9e $
C) 24 cm from $ +e $
D) 12 cm from $ +e $
Show Answer
Answer:
Correct Answer: B
Solution:
Suppose q is placed at a distance x from +9e, then for equilibrium net force on it must be zero i.e. $ | F _{1} |=| F _{2} | $ Which gives $ x _{1}=\frac{x}{\sqrt{\frac{Q _{2}}{Q _{1}}}+1}=\frac{16}{\sqrt{\frac{e}{9e}}+1}=12cm $
