MCQ
A force $‘F’$ is acting between two charges in air. If the space between them be completely filled with a medium $K = 4$, the force will be:
- A$F$
- B$4F$
- ✓$\frac{\text{F}}{4}$
- D$2F$
✓
Answer
Correct option: C.
$\frac{\text{F}}{4}$
C. $\frac{ F }{4}$
Explanation:
By Coulomb's law, the force between two charges $\left(q_1, q_2\right)$ in air is given by
$F =\frac{ q _1 q _2}{4 \pi \epsilon_0 r ^2}$
where $r =$ distance between two charges.
Now the force between two charges $\left(q_1, q_2\right)$ in medium with dielectric constant $K =4$ becomes, $F =\frac{ q _1 q _2}{4 \pi K \epsilon_0 r ^2}$
So, $F=\frac{ F }{ K }=\frac{ F }{4}$
Explanation:
By Coulomb's law, the force between two charges $\left(q_1, q_2\right)$ in air is given by
$F =\frac{ q _1 q _2}{4 \pi \epsilon_0 r ^2}$
where $r =$ distance between two charges.
Now the force between two charges $\left(q_1, q_2\right)$ in medium with dielectric constant $K =4$ becomes, $F =\frac{ q _1 q _2}{4 \pi K \epsilon_0 r ^2}$
So, $F=\frac{ F }{ K }=\frac{ F }{4}$
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