# IB Physics Electric and Magnetic Fields

A tutorial sheet on electric and magnetic fields follows.

1. A charge +Q is at rest in the laboratory. Show the electric field around the charge in the laboratory reference frame.
2. A charge +Q moves to the right at a constant velocity v relative to the laboratory. Draw the electric field of the charge (i) in the reference frame of the charge, (ii) in the laboratory reference frame.
3. Two charges, +Q and +Q, both move to the right at a constant velocity v relative to the laboratory on parallel paths. In the reference frame of the charges, the line joining the charges is perpendicular to the velocity of the charges and has length d. Determine the magnitude of the force between the charges in (i) the reference frame of the charges, (ii) the laboratory reference frame.
4. A current I flows in the same direction in each of two long parallel wires. Determine the force between the wires in (i) the laboratory reference frame, (ii) a refernce frame moving parallel to the wires at the speed of the charges.
5. An electric field exists in the laboratory reference frame S. A reference frame S' moves at a constant velocity relative to the laboratory frame. (i) is an electric field present in s' ? (ii) is a magnetic field present in S' ?
6. A magnetic field exists in the laboratory reference frame S. A reference frame S' moves at a constant velocity relative to the laboratory frame. (i) is an electric field present in S' ? (ii) is a magnetic field present in S' ?
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