HSC Physics Electricity and Magnetism

In the Electricity and Magnetism section of the HSC Physics Formuae Sheet the equations involving an angle 𝜽 do not all have the angle measured in the same way. A tutorial set of substitution questions is given below.

1. A charge of +2.0 μC has a velocity of 3.0×107 ms-1 to the right of the page. The particle is in a uniform magnetic field of 1.0 mT acting out of the page. Determine the magnetic force acting on the charge.
2. A coil of area 10 cm2 has its plane at an angle of 30° to a uniform magnetic field of 100 mT. What is the magnetic flux through the coil?
3. A coil of cross sectional area 30 mm2 containing 100 turns carries a current of 20 mA. The axis of the coil makes an angle of 20° with a uniform magnetic field of 2.0x10-2 T. Determine the size of the torque acting on the current.
4. A straight wire of length 52 cm carries a current of 300 μA in a uniform magnetic field of 350 mT. If the wire makes an angle of 123° with the magnetic field lines, find the size of the magnetic force acting on the current.
5. The Earth's magnetic field vector at Sydney is 57 μT N12°36'E at 64°19' below the horizontal. At a certain instant an electron is moving in this magnetic field towards the east at a speed of 3.0x107 ms-1. Determine (a) the magnitude of the magnetic force acting on the electron at this instant (b) the direction of the magnetic force acting at this instant, and (c) the period of the motion of the electron in the uniform magnetic field.
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