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#electric field zero

6 public questions tagged with this topic.

Superposition Principle and Equilibrium of Charges

Two charges \( +15 \, \mu\text{C} \) and \( -5 \, \mu\text{C} \) are 75 cm apart. What is the distance from \( +15 \, \m

**Independent action of charges** allows total force or field as vector sum. Geometry dictates distances to evaluation point, and resultant follows Σ k q_i/r_i², explaining zero field at symmetric centres for equal charges. Let x be distance from +15 μC , then 0.75 - x from -5 μC . (15 × 10⁻⁶/x²) = (5 × 10⁻⁶/(0.75 - x)²) , 15 (0.75 - x)² = 5 x² . 3 (0.5625 - 1.5 x + x²) = x² , 1.6875 - 4.5 x + 3 x² = x² . 2 x² - 4.5 x + 1.6875 = 0 , x = (4.5 ± √(20.25 - 13.5)/4) =

Ref: NCERT > Physics Book > Electric Charges and Fields > Superposition Principle and Equilibrium of Charges

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Coulomb's Law and Force Between Point Charges

Two charges \( +6 \, \mu\text{C} \) and \( -4 \, \mu\text{C} \) are 25 cm apart. What is the distance from \( +6 \, \mu\

**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. Let distance from +6 μC be x , then from -4 μC is 0.25 - x . (k × 6 × 10⁻⁶/x²) = (k × 4 × 10⁻⁶/(0.25 - x)²) . (6/x²) = (4/(0.25 - x)²) , 6 (0.25 - x)² = 4 x² . 6 (0.0625 - 0.5 x + x²) = 4 x² , 0.375 - 3 x + 6 x² = 4

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

Two charges \( +10 \, \mu\text{C} \) and \( -2 \, \mu\text{C} \) are 80 cm apart. What is the distance from \( +10 \, \m

**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. Let x be distance from +10 μC , then 0.8 - x from -2 μC . (10 × 10⁻⁶/x²) = (2 × 10⁻⁶/(0.8 - x)²) , 10 (0.8 - x)² = 2 x² . 5 (0.64 - 1.6 x + x²) = x² , 3.2 - 8 x + 5 x² = x² . 4 x²

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

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Coulomb's Law and Force Between Point Charges

Two charges \( +12 \, \mu\text{C} \) and \( -3 \, \mu\text{C} \) are 60 cm apart. What is the distance from \( +12 \, \m

**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. Let x be distance from +12 μC , then 0.6 - x from -3 μC . (12 × 10⁻⁶/x²) = (3 × 10⁻⁶/(0.6 - x)²) , 12 (0.6 - x)² = 3 x² . 4 (0.36 - 1.2 x + x²) = x² , 1.44 - 4.8 x + 4 x² = x² . 3 x² - 4.8 x + 1.44 = 0 , x

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

Two charges \( +12 \, \mu\text{C} \) and \( -4 \, \mu\text{C} \) are 90 cm apart. What is the distance from \( +12 \, \m

**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. Let x be distance from +12 μC , then 0.9 - x from -4 μC . (12 × 10⁻⁶/x²) = (4 × 10⁻⁶/(0.9 - x)²) , 12 (0.9 - x)² = 4 x² . 3 (0.81 - 1.8 x + x²) = x² , 2.43 - 5.4 x + 3 x² = x² . 2 x² - 5.4 x + 2.43 = 0 , x

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

Two charges \( +14 \, \mu\text{C} \) and \( -6 \, \mu\text{C} \) are 100 cm apart. What is the distance from \( +14 \, \

**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. Let x be distance from +14 μC , then 1 - x from -6 μC . (14 × 10⁻⁶/x²) = (6 × 10⁻⁶/(1 - x)²) , 14 (1 - x)² = 6 x² . 14 (1 - 2 x + x²) = 6 x² , 14 - 28 x + 14 x² = 6 x² . 8 x² - 28 x + 14 = 0

Ref: NCERT > Physics Book > Electric Charges and Fields > Coulomb's Law and Force Between Point Charges

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