Easy MCQ +4 / -1 PYQ · JEE Mains 2024

An electric field is given by $(6 \hat{i}+5 \hat{j}+3 \hat{k}) \mathrm{N} / \mathrm{C}$. The electric flux through a surface area $30 \hat{i} \mathrm{~m}^2$ lying in YZ-plane (in SI unit) is :

  1. A 60
  2. B 90
  3. C 180 Correct answer
  4. D 150

Solution

<p>$$\begin{aligned} & \overrightarrow{\mathrm{E}}=6 \hat{\mathrm{i}}+5 \hat{\mathrm{j}}+3 \hat{\mathrm{k}} \\ & \overrightarrow{\mathrm{A}}=30 \hat{\mathrm{i}} \\ & \phi=\overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{A}} \\ & \phi=(6 \hat{\mathrm{i}}+5 \hat{\mathrm{j}}+3 \hat{\mathrm{k}}) \cdot(30 \hat{\mathrm{i}}) \\ & \phi=6 \times 30=180 \end{aligned}$$</p>

About this question

Subject: Physics · Chapter: Electrostatics · Topic: Coulomb's Law

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