Physics · Magnetic field due to a magnetic dipole (bar magnet) along its axis and perpendicular to its axis, torque on a magnetic dipole in a uniform magnetic field
The force between two magnetic poles is when they are separated by certain dista
The force between two magnetic poles is \( F \) when they are separated by certain distance. If the distance between the two poles is doubled and strength of each pole is tripled. The percentage change in the force between the two poles is :
- A. \( 125 \% \)
- B. \( 100 \% \)
- C. \( 50 \% \)
- D. \( 25 \% \)
Step-by-step solution
Using Coulomb's law for magnetism: F = k * m1 * m2 / r^2. Initially, F = k * m^2 / r^2. After tripling strength and doubling distance: F' = k * (3m * 3m) / (2r)^2 = (9/4) * (k m^2 / r^2) = 2.25 F. Change = F' - F = 1.25 F. Percentage change = (1.25 F / F) * 100% = 125%.
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