An electric field vector E = (2xi)NC^{-1} exists in space. A cube of side 2m is placed in the space as per figure given below.

Question

An electric field \(\overrightarrow{\mathrm{E}}=(2 x \hat{\mathrm{i}}) \mathrm{NC}^{-1}\) exists in space. \(\mathrm{A}\) cube of side \(2 \mathrm{m}\) is placed in the space as per figure given below. The electric flux through the cube is............ \(\mathrm{Nm}^{2} / \mathrm{C}\). 

 

Answer 1

Correct answer is :  16 

 

\(\overrightarrow{\mathrm{E}}=2 x \hat{\mathrm{i}}\)

\(\phi=\overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{A}}\) 

 \(\phi_{\text {in }}=-4 \times 4=-16\ \mathrm{Nm}^{2} / \mathrm{c}\)

\(\phi_{\text {out }}=8 \times 4=32 \mathrm{Nm}^{2} / \mathrm{c}\)

\(\mathrm{d}_{\text {net }}=\phi_{\text {in }+} \phi_{\text {out }}=-16+32=16 \ \mathrm{Nm}^{2} / \mathrm{c}\)