Q1. Two identical charges are placed 1 m apart. If the distance is reduced to 0.5 m, how does the force between them change? (2022)
Solution:
According to Coulomb's law, F ∝ 1/r². Reducing the distance to half increases the force by a factor of 4.
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Q2. If the charge on a capacitor is doubled, what happens to the electric field between the plates? (2022)
Solution:
The electric field E between the plates of a capacitor is directly proportional to the charge. If the charge is doubled, the electric field also doubles.
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Q3. If the charge on an object is tripled, what happens to the electric field produced by that charge? (2020)
Solution:
The electric field E is directly proportional to the charge, so tripling the charge will triple the electric field.
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Q4. What is the electric field due to a point charge of +10 µC at a distance of 0.1 m? (2023)
Solution:
Electric field E = k * |q| / r² = (9 × 10^9 N m²/C²) * (10 × 10^-6 C) / (0.1 m)² = 9000 N/C.
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Q5. A charge of +5 µC is placed in an electric field of 300 N/C. What is the work done in moving the charge 0.2 m in the direction of the field? (2019)
Solution:
Work done W = F * d = (E * q) * d = (300 N/C * 5 × 10^-6 C) * 0.2 m = 0.3 J.
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Q6. If a charge of +1 µC is placed in an electric field of 2000 N/C, what is the force acting on the charge? (2021)
Solution:
Force F = qE = (1 × 10^-6 C) * (2000 N/C) = 0.002 N.
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Q7. A charge of -2 µC is placed in an electric field of 500 N/C. What is the direction of the force acting on the charge? (2023)
Solution:
The force on a negative charge is in the direction opposite to the electric field, hence towards the positive charge.
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Q8. If a charge of +1 µC is placed in an electric field of 1000 N/C, what is the force experienced by the charge? (2019)
Solution:
Force F = qE = (1 × 10^-6 C) * (1000 N/C) = 0.001 N.
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Q9. What happens to the electric field when the charge is doubled while keeping the distance constant? (2023)
Solution:
The electric field E is directly proportional to the charge, so if the charge is doubled, the electric field also doubles.
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Q10. Which of the following is a property of electric field lines? (2023)
Solution:
Electric field lines cannot intersect because it would imply two different directions of the electric field at a point.
