Electricity and Magnetism - SS1 Physics Past Questions and Answers - page 3

Changing the velocity of a charged particle affects the magnitude of the magnetic force but not its direction. Doubling the velocity doubles the magnitude of the magnetic force. Changing the charge of the particle also affects the magnitude of the magnetic force. Doubling the charge doubles the magnitude of the force. Finally, changing the magnetic field strength affects both the magnitude and direction of the magnetic force. Doubling the magnetic field strength doubles the magnitude of the force, and changing the direction of the magnetic field changes the direction of the force.

The induced emf can be calculated using Faraday's law:

   induced emf = -N x (ΔΦ/Δt)

   where N is the number of turns, ΔΦ is the change in magnetic flux, and Δt is the change in time.

   Given: N = 200 turns, ΔΦ/Δt = 0.02 T/s

   induced emf = -200 x 0.02 = -4 V

The magnitude of the induced emf can be calculated using Faraday's law:

   induced emf = -N x (ΔΦ/Δt)

   The change in magnetic flux can be calculated as ΔΦ = B x A, where B is the magnetic field and A is the area of the loop.

   Given: r = 0.1 m, B = 0.5 T, Δt = 0.1 s

   Area of the loop, A = π x r2 = 3.14 x (0.1)2 = 0.0314 m2

   ΔΦ = B x A = 0.5 x 0.0314 = 0.0157 Wb

   induced emf = -N x (ΔΦ/Δt) = -1 * (0.0157/0.1) = -0.157 V

 The magnitude of the induced emf can be calculated using Faraday's law:

   induced emf = -N x (ΔΦ/Δt)

   The change in magnetic flux can be calculated as ΔΦ = B x A, where B is the magnetic field and A is the area of the coil.

   Given: N = 500 turns, B = 0.02 T, Δt = 50 T/s

   Area of the coil, A = (π x r2) = (π x (0.1)2) = 0.0314 m2

   ΔΦ = B x A = 0.02 x 0.0314 = 0.000628 Wb

   induced emf = -N x (ΔΦ/Δt) = -500 x (0.000628/50) = -0.00628 V