#static electricity

Coulomb's Law and Force Between Point Charges

A body acquires a charge of \( -9.6 \times 10^{-8} \, \text{C} \) when rubbed. How many electrons were transferred to it

**Inverse-square law** for charges states F ∝ 1/r² while increasing with charge product. Using k = 9×10⁹ N·m²/C², force at distance r follows F = k q₁q₂/r², forming basis for pairwise force calculation. Negative charge indicates electrons gained. q = n e , e = -1.6 × 10⁻¹⁹ C . n = (q/|e|) = (9.6 × 10⁻⁸/1.6 × 10⁻¹⁹) = 6 × 10¹¹ . Substituting values gives 6 × 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 glass rod is rubbed with silk and acquires a charge of \( +2.5 \times 10^{-7} \, \text{C} \). How many electrons were

**Inverse-square law** for charges states F ∝ 1/r² while increasing with charge product. Using k = 9×10⁹ N·m²/C², force at distance r follows F = k q₁q₂/r², forming basis for pairwise force calculation. Charge on glass rod is positive, so electrons are transferred from glass to silk. Charge of one electron e = -1.6 × 10⁻¹⁹ C . Number of electrons: n = (q/|e|) = (2.5 × 10⁻⁷/1.6 × 10⁻¹⁹) = 1.5625 × 10¹² . Substituting values gives 1.56 × 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 > 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

Which principle explains why rubbing two neutral objects can result in one becoming positively charged and the other neg

**Fundamental property of charge** includes additivity and quantization, meaning net charge equals algebraic sum of constituents and each is multiple of e. When rod loses charge, electron removal is inferred, and n = q/e gives transferred count. The conservation of charge ensures that the total charge remains zero. Rubbing transfers electrons from one object to another due to differing electron affinities, leaving one with a net positive charge (electron loss) and the other negative (electron gain). Substituting values gives Conservation of charge, 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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Electric Charge, Quantization and Conservation

A glass rod loses \( 9.6 \times 10^{-8} \, \text{C} \) of charge when rubbed with silk. How many electrons were transfer

**Fundamental property of charge** includes additivity and quantization, meaning net charge equals algebraic sum of constituents and each is multiple of e. When rod loses charge, electron removal is inferred, and n = q/e gives transferred count. Losing charge means electrons are removed, so charge is positive. q = n e , e = 1.6 × 10⁻¹⁹ C . n = (q/|e|) = (9.6 × 10⁻⁸/1.6 × 10⁻¹⁹) = 6 × 10¹¹ . Substituting values gives 6 × 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 > Electric Charge, Quantization and Conservation

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Electric Charge, Quantization and Conservation

A body gains a charge of \( -1.6 \times 10^{-7} \, \text{C} \) when rubbed. How many electrons were transferred to it?

**Quantization of charge** states observable charge is integer multiple of elementary charge e = 1.6×10⁻¹⁹ C, q = n·e, and total charge is conserved in isolated systems. Loss of electrons produces positive charge, and number of transferred electrons follows n = q/e, linking macroscopic charge measurement to microscopic carriers. Negative charge means electrons gained. q = n e , e = -1.6 × 10⁻¹⁹ C . n = (q/|e|) = (1.6 × 10⁻⁷/1.6 × 10⁻¹⁹) = 1 × 10¹² . Substituting values gives 1 × 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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Electric Charge, Quantization and Conservation

A glass rod loses \( 6.4 \times 10^{-8} \, \text{C} \) of charge when rubbed with silk. How many electrons were transfer

**Quantization of charge** states observable charge is integer multiple of elementary charge e = 1.6×10⁻¹⁹ C, q = n·e, and total charge is conserved in isolated systems. Loss of electrons produces positive charge, and number of transferred electrons follows n = q/e, linking macroscopic charge measurement to microscopic carriers. Losing charge means electrons are removed, so charge is positive. q = n e , e = 1.6 × 10⁻¹⁹ C . n = (q/|e|) = (6.4 × 10⁻⁸/1.6 × 10⁻¹⁹) = 4 × 10¹¹ . Substituting values gives 4 × 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 > Electric Charge, Quantization and Conservation

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