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In figure a point charge $+Q_1$ is at the centre of an imaginary spherical surface and another point charge $+Q_2$ is outside it. Point $P$ is on the surface of the sphere. Let ${\Phi _s}$be the net electric flux through the sphere and ${\vec E_p}$ be the electric field at point $P$ on the sphere. Which of the following statements is $TRUE$ ?
Both charges $+Q_1$ and $+Q_2$ make nonzero contributions to $\phi _S$ but only the charge $+Q_1$ makes a nonzero contribution to ${\vec E_P}$ .
Both charges $+Q_1$ and $+Q_2$ make nonzero contributions to $\phi _S$ but only the charge $+Q_2$ makes a nonzero contribution to ${\vec E_P}$ .
Only the charge $+Q_1$ makes a nonzero contribution to $\phi _S$ but both charges $+Q_1$ and $+Q_2$ make nonzero contributions to ${\vec E_P}$ .
Only the charge $+Q_2$ makes a nonzero contribution to $\phi _S$ but both charges $+Q_1$ and $+Q_2$ make nonzero contributions to ${\vec E_P}$ .
Solution
${\phi _s} = \frac{{{Q_1}}}{{{ \in _0}}}$ only because of $Q_{1}$
$\overrightarrow{\mathrm{E}}_{\mathrm{P}}=\overrightarrow{\mathrm{E}}_{1}+\overrightarrow{\mathrm{E}}_{2}$ because of $\mathrm{Q}_{1} $ and $ \mathrm{Q}_{2}$ both
