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#plastic rod

3 public questions tagged with this topic.

Coulomb's Law and Force Between Point Charges

A plastic rod gains a charge of \( -1.28 \times 10^{-7} \, \text{C} \) when rubbed. How many electrons were transferred

**Electrostatic force** described by F = (1/4π ε₀)·q₁q₂/r² obeys Newton's third law. Magnitude depends on q₁q₂ and 1/r², enabling quantitative estimation at given separation, with sign indicating attraction or repulsion. Negative charge means electrons gained. q = n e , e = -1.6 × 10⁻¹⁹ C . n = (q/|e|) = (1.28 × 10⁻⁷/1.6 × 10⁻¹⁹) = 8 × 10¹¹ . Substituting values gives 8 × 10¹¹, 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 > Coulomb's Law and Force Between Point Charges

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Coulomb's Law and Force Between Point Charges

A plastic rod gains \( 4.8 \times 10^{-8} \, \text{C} \) of negative charge when rubbed. How many electrons were transfe

**Coulomb's law** gives force between point charges as F = k·|q₁q₂|/r², k = 1/(4π ε₀) = 9×10⁹ N·m²/C², directed along line joining charges. Like charges repel, opposite attract, magnitude scales with product of charges and inverse square of separation r². Negative charge means electrons are gained. q = n e , e = -1.6 × 10⁻¹⁹ C . n = (q/|e|) = (4.8 × 10⁻⁸/1.6 × 10⁻¹⁹) = 3 × 10¹¹ . Substituting values gives 3 × 10¹¹, 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 > Coulomb's Law and Force Between Point Charges

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Electric Charge, Quantization and Conservation

A plastic rod gains a charge of \( -1.92 \times 10^{-7} \, \text{C} \) when rubbed. How many electrons were transferred

**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. Negative charge means electrons gained. q = n e , e = -1.6 × 10⁻¹⁹ C . n = (q/|e|) = (1.92 × 10⁻⁷/1.6 × 10⁻¹⁹) = 1.2 × 10¹² . Substituting values gives 1.2 × 10¹², 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 > Electric Charge, Quantization and Conservation

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