A) 15 N
B) 320 N
C) 5 N
D) 32 N
Correct Answer: C
Solution :
From Coulombs law the force between two charges is \[F=\frac{1}{4\pi {{\varepsilon }_{0}}K}.\frac{{{q}_{1}}{{q}_{2}}}{{{r}^{2}}}\] where r is distance between the charges and K the dielectric constant. In air: \[{{F}_{1}}=\frac{1}{4\pi {{\varepsilon }_{0}}K}.\frac{{{q}_{1}}{{q}_{2}}}{{{r}^{2}}}=40\,N\] In glass: \[{{F}_{2}}=\frac{1}{4\pi {{\varepsilon }_{0}}}.\frac{{{q}_{1}}{{q}_{2}}}{8{{r}^{2}}}\] \[\therefore \] \[\frac{{{F}_{1}}}{{{F}_{2}}}=\frac{40}{{{F}_{2}}}=8\] \[\Rightarrow \] \[{{F}_{2}}=5\,N\]You need to login to perform this action.
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