- Home
- Standard 12
- Physics
1. Electric Charges and Fields
medium
The charges on two sphere are $+7\,\mu C$ and $-5\,\mu C$ respectively. They experience a force $F$. If each of them is given and additional charge of $-2\,\mu C$, the new force of attraction will be
A
$F$
B
$F / 2$
C
$F/\sqrt 3 $
D
$2F$
Solution
(a) $F = \frac{1}{{4\pi {\varepsilon _0}}}\frac{{( + 7 \times {{10}^{ – 6}})\,( – 5\, \times {{10}^{ – 6}})}}{{{r^2}}} = – \frac{1}{{4\pi {\varepsilon _0}}}\frac{{35 \times {{10}^{12}}}}{{{r^2}}}\,N$
$F' = \frac{1}{{4\pi {\varepsilon _0}}}\frac{{( + 5 \times {{10}^{ – 6}})( – 7 \times {{10}^{ – 6}})}}{{{r^2}}} = – \frac{1}{{4\pi {\varepsilon _0}}}\frac{{35 \times {{10}^{12}}}}{{{r^2}}}\,N$
Standard 12
Physics
