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#microcoulomb

2 public questions tagged with this topic.

A charge of \( 8 \, \mu\text{C} \) is at the center of a cube of edge 25 cm. What is the total flux through the cube?

**Gauss's theorem** states total flux through closed surface equals enclosed charge divided by free-space permittivity, Φ_total = q_enc/ε₀, ε₀ = 8.854×10⁻¹² C²/(N·m²). Result independent of shape or size, depends only on net enclosed charge, enabling charge determination from flux. Total flux: Φ = (q/ε₀) . Φ = (8 × 10⁻⁶/8.854 × 10⁻¹²) = 9.03 × 10⁵ N·m²/C . Substituting values gives 9.03 × 10⁵ N·m²/C, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.

Ref: NCERT > Physics Book > Electric Charges and Fields > Gauss's Theorem and Total Flux

Two charges \( +3 \, \mu\text{C} \) and \( -3 \, \mu\text{C} \) are 15 cm apart. What is the force on a \( 2 \, \mu\text

**Charge conservation and quantization** govern rubbing processes where electrons transfer without creation. Total charge before and after remains equal, and any measured charge corresponds to n = q/e electrons, allowing counting of carriers from coulomb value. Electric field at midpoint: E₁ = 9 × 10⁹ × (3 × 10⁻⁶/(0.075)²) = 4.8 × 10⁶ N/C (towards -3 μC ). E₂ = 4.8 × 10⁶ N/C (towards -3 μC ). Net E = 4.8 × 10⁶ + 4.8 × 10⁶ = 9.6 × 10⁶ N/C . Force: F = q E = 2 × 10⁻⁶ × 9.6 × 10⁶ = 19.2 N . Substituting values gives 19.2

Ref: NCERT > Physics Book > Electric Charges and Fields > Electric Charge, Quantization and Conservation