Presentation on theme: "Baby-Quiz 1.Which of the following affects the resistance of a wire: diameter, type of material, length, or temperature? Explain. 2.Which circuit offers."— Presentation transcript:
Baby-Quiz 1.Which of the following affects the resistance of a wire: diameter, type of material, length, or temperature? Explain. 2.Which circuit offers the greater resistance to to battery, two bulbs in series or two bulbs in parallel? Why? 3.If a string of five bulbs in series is added in parallel to a single- bulb circuit, you find that the brightness of the original bulb does not change. Has the current through the battery increased, decreased, or stayed the same? Has the resistance of the circuit increased, decreased, or stayed the same? Explain. 4.What happens to the power supplied to a battery if the resistance connected to the battery is doubled? Why/
Direction of Magnetic Field Produced by a Current-Carrying Wire: Right-Hand Rule
Grasp the wire with your right hand so that your thumb points in the direction of the conventional (positive) current; then your fingers will encircle the wire in the direction of the magnetic field.
Force on an Electric Current in a Magnetic Field.
Important: the direction of the force is always perpendicular to the direction of the current and also perpendicular to the direction of the magnetic field.
Important: right-hand rule defines direction of a force acting on a positive charge. For negatively charged particles the force is in exactly the opposite direction. Don’t forget this when you are answering questions about electrons!!!
Proton’s Path in a Uniform Magnetic Field A proton travels at velocity v in a plane perpendicular to a magnetic field. Describe its path.
Conceptual Example: A Spiral Path What is the path of a charged particle if its velocity is not perpendicular to the magnetic field?