13.1: The charge of how many negatively charged particles would be equal to 100 µC. Assume charge on one negative particle is 1.6 𝐱 10⁻¹⁹ C ? Ans. (6.25 𝐱 10¹⁴ )


13.2: Two point charges q₁= 10 µC and q₂= 5 µC are placed at a distance of 150 cm. What will be the Coulomb's force between them? Also find the direction of the force. Ans. (0.2 N, the direction of repulsion)


13.3: The force of repulsion between two identical positive charges is 0.8 N, when the charges are 0.1 m apart. Find the value of each charge.  Ans. (9.4 𝐱 10⁻⁷ C)


13.4: Two charges repel each other with a force of 0.1 N when they are 5 cm apart. Find the forces between the same charges when they are 2 cm apart. Ans. (0.62 N)


13.5: The electric potential at a point in an electric field is 104 V. If a charge of +100 µC is brought from infinity to this point, what would be the amount of work done on it? Ans.(1 J)


13.6: A point charge of +2C is transferred from a point at potential 100V to a point at potential 50V. What would be the energy supplied by the charge? Ans. (100 J)


13.7: A capacitor holds 0.06 coulombs of charge when fully charged by a 9 volt battery. Calculate capacitance of the capacitor. Ans. (6.67 𝐱10⁻³ F)


13.8: A capacitor holds 0.03 coulombs of charge when fully charged by a 6 volt battery. How much voltage would be required for it to hold 2 coulombs of charge? Ans.(400 V)

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13.9: Two capacitors of capacitances 6 µF and 12 µF are connected in series with 12 V battery. Find the equivalent capacitance of the combination. Find the charge and the potential difference across each capacitor. Ans. (4 µF, 48 µC, 8 V, 4 V)


13.10: Two capacitors of capacitances 6 µF and 12 µF are connected in parallel with 12V battery. Find the equivalent capacitance of the combination. Find the charge and the potential difference across each capacitor. Ans. (18 µF, 72 µC, 144 µC, 12 V)