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⚛️ Physics  ·  Electric Charges and Fields  ·  NEET & JEE

A charge q is placed at one vertex of a cube. The electric flux through each of the three faces that do not contain that vertex is:

Answer: q/(24 0 ).

  • A q/(24&epsilon;<sub>0</sub>)
  • B q/(8&epsilon;<sub>0</sub>)
  • C q/(12&epsilon;<sub>0</sub>)
  • D q/(6&epsilon;<sub>0</sub>)

Correct answer: A. q/(24&epsilon;<sub>0</sub>)

Explanation: Eight identical cubes can be joined with the charge at the common centre, giving total flux q/&epsilon;<sub>0</sub>. Each cube gets q/(8&epsilon;<sub>0</sub>), shared equally among its three outer faces, giving q/(24&epsilon;<sub>0</sub>) per face.

Field Lines: Single Charge vs Electric Dipole+isolated +charge: lines radiate outward, all directions+dipole: lines curve from + to − (denser between them)

Field lines always point from positive to negative charge, are denser where the field is stronger, and never cross; an isolated positive charge has lines radiating symmetrically outward, while a dipole's lines curve from the positive to the negative charge.

Concept context

Coulomb's law, electric field, potential, capacitors, Gauss's law.

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