Select true or false for each statement below:

1. [ ] changing magnetic flux can induce an emf in a circuit.

2. [ ] the magnitude of induced emf (or electric field) is inversely proportional to the time rate of changes of magnetic flux through the circuit.

3. [ ] lenz's law can be used to determine the direction of the induced emf or current.

4. [ ] an electric field is induced by a changing magnetic flux, even in free space, without a conductor.

5. [ ] maxwell's four equations, together with the lorentz force law, give a complete description of all classical electromagnetic interactions.

6. [ ] a large, steady magnetic flux through a circuit induces a large emf.

7. [ ] a motional emf could be generated within a piece of a conductor, as the conductor moves through a uniform magnetic field.

8. [ ] lenz's law states that the induced current and induced emf in a conductor are in such a direction as to enhance the magnetic flux change that produced them.

9. [ ] an induced electric field is a conservative field, just like a static electric field.

Comedians like to joke that the reason we haven’t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earth’s broadcasts of intellectually embarrassing tv programs, like gilligan’s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. let’s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame

How can you increase the strength of an electromagnet?

Which statement correctly describes the interaction between magnetic poles? north and south poles attract each other. north and south poles repel each other. two north poles will attract each other. two south poles will attract each other.