Suppose you are holding a circular ring of wire in front of you and suddenly thrust a magnet, south pole first, away from you toward the center of the circle. Is a current induced in the wire? Explain your answer.

A simple generator has a square armature $6.0 \mathrm{~cm}$ on a side. The armature has $85$ turns of $0.65 \mathrm{~cm}$ diameter copper wire and rotates in a $0.65 \mathrm{~T}$ magnetic field. The generator is used to power a lightbulb rated at $12.0 \mathrm{~V}$ and $25.0 \mathrm{~W}$. At what rate should the generator rotate to provide $12.0 \mathrm{~V}$ to the bulb? Consider the resistance of the wire on the armature.

Calculate the peak output voltage of a simple generator whose square armature windings are $5.50 \mathrm{~cm}$ on a side; the armature contains $125$ loops and rotates in a field of $0.200 \mathrm{~T}$ at a rate of $120 \mathrm{rev} / \mathrm{s}$.

A generator rotates at $85 \mathrm{~Hz}$ in a magnetic field of $0.030 \mathrm{~T}$. It has $950$ turns and produces an rms voltage of $150 \mathrm{~V}$ and an rms current of $60.0 \mathrm{~A}$. What is the area of each turn of the coil?

Find the angle of inclination θ of the tangent plane to the surface x² + y² + z² = 14 at the point(2, 1, 3).

A generator rotates at $85 \mathrm{~Hz}$ in a magnetic field of $0.030 \mathrm{~T}$. It has $950$ turns and produces an rms voltage of $150 \mathrm{~V}$ and an rms current of $60.0 \mathrm{~A}$. What is the peak current produced?

You are lying in bed and want to shut your bedroom door. You have a bouncy "superball" and a blob of clay, both with the same mass. Which one would be more effective to throw at your door to close it? $(a)$ The superball. $(b)$ The blob of clay. $(c)$ Both the same. $(d)$ Neither will work.

"You are lying in bed and want to shut your bedroom door. You have a bouncy ball and a blob of clay, both with the same mass. Which one would be more effective to throw at your door to close it? $(a)$ The ball. $(b)$ The blob of clay. $(c)$ Both are the same. $(d)$ Neither will work."

The space shuttle, in circular orbit around the Earth, collides with a small asteroid which ends up in the shuttle's storage bay. For this collision, $(a)$ only momentum is conserved. $(b)$ only kinetic energy is conserved. $(c)$ both momentum and kinetic energy are conserved. $(d)$ neither momentum nor kinetic energy is conserved.

A type of magnetic switch similar to a solenoid is a relay. A relay is an electromagnet (the iron rod inside the coil does not move) which, when activated, attracts a piece of iron on a pivot. Design a relay to close an electrical switch. A relay is used when you need to switch on a circuit carrying a very large current but you do not want that large current flowing through the main switch. For example, the starter switch of a car is connected to a relay so that the large current needed for the starter doesn't pass to the dashboard switch.

A type of magnetic switch similar to a solenoid is a relay. A relay is an electromagnet (the iron rod inside the coil does not move) which, when activated, attracts a piece of iron on a pivot. Design a relay to close an electrical switch. A relay is used when you need to switch on a circuit carrying a very large current but you do not want that large current flowing through the main switch. For example, the starter switch of a car is connected to a relay so that the large current needed for the starter doesn't pass to the dashboard switch.

Why does twisting the lead-in wires to electrical devices reduce the magnetic effects of the leads?

A $280$-loop circular armature coil with a diameter of $10.0 \mathrm{~cm}$ rotates at $120 \mathrm{rev} / \mathrm{s}$ in a uniform magnetic field of strength $0.45 \mathrm{~T}$. What would you do to the rotation frequency in order to double the rms voltage output?

A $280$-loop circular armature coil with a diameter of $10.0 \mathrm{~cm}$ rotates at $120 \mathrm{rev} / \mathrm{s}$ in a uniform magnetic field of strength $0.45 \mathrm{~T}$. What is the rms voltage output of the generator?