Asmall glass bead has been charged to + 30 nc . a tiny ball bearing 1.0 cm above the bead feels a 1.8×10^−2 n downward electric force. what is the charge on the ball bearing?

The charge on the ball bearing = 667 nC or 6.67 × 10⁻⁷ C

Explanation:

Coulombs law: The force of attraction or repulsion between two charges, Q₁ and Q₂, is directly proportional to the product of the charges and inversely proportional to the square of the distance between the two charges

From coulombs law, F =1/4πε₀ (Q₁Q₂/r²) Equation 1

making Q₂ the subject of the equation,

Q₂ =( F×r²)/(Q₁×1/4πε₀) Equation 2

Where F = force of attraction, Q₁ = charge of the bead, Q₂ = charge of the ball bearing, r = distance between the bead and the ball bearing.

Given: Q₁ = 30 nC = 30×10⁻⁹ C,  F = 1.8×10⁻² N,

             r = 1.0 cm = (1/100) = 0.01 m

Constant: 1/4πε₀ = 9×10⁹ Nm²/C²

Substituting these values intto equation 2,

Q₂ = [(1.8×10⁻²)(0.01)²]/[(9×10⁹)(30×10⁻⁹)]

Q₂ = (1.8×10⁻² × 0.0001)/270

Q₂ = 6.67 × 10⁻⁷ C. = 667 nC

Therefore the charge on the ball bearing = 667 nC

think its the third option

probably not the "magnets"in the magnet, so to speak, are thought to be electrons orbiting in shells. vurrent loops two sides to the loop