Physics · Electrostatics
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A spherical liquid drop has a diameter of 2cm and is given a charge of 1mC. The potential at the surface of the drop is:
- A
9 MV
- B
900 MV
- C
0.45 MV
- D
4.5 MV
The electric potential at the surface of a spherical charged object is given by the formula V = kQ/R, where:
- k (Coulomb's constant) = 9 × 109 N·m²/C²
- Q = 1 mC = 1 × 10-3 C
- R is the radius of the sphere, which is half the diameter, i.e., 1 cm = 0.01 m
Substituting these values into the formula, we get V = (9 × 109 N·m²/C²) × (1 × 10-3 C) / 0.01 m = 900 MV.
Options A, C, and D are incorrect because they result from either incorrect conversion of units or wrong application of the formula.
Incorrect. This calculation underestimates the potential by not converting the charge or radius correctly.
Correct. The potential at the surface is calculated using the formula V = kQ/R, where k is the electrostatic constant, Q is the charge, and R is the radius of the sphere.
Incorrect. This calculation significantly underestimates the potential, likely due to an error in the radius conversion or charge magnitude.
Incorrect. This result is incorrect because it does not account for the correct usage of the formula or units involved in the calculation.
Tagged under Physics · Electrostatics · 2024