Physics 7. Homework # 5

Due: 5/3

1)      What was the motivation for hypothesizing the existence of the ether?

a)      The idea that motion cannot occur in a vacuum

b)      The belief that light needs a medium to propage in, like any other wave

c)      That it simplifies Maxwell’s equations

d)     That is required by Newton’s equations

2)      What is one difference between microwaves and X-rays?

a)      They are both electromagnetic waves distinguished only by their wavelength, which is much smaller for X-rays

b)      Their very nature: X-rays are produced by magnets and not by moving charges while microwaves require electricity and no magnets.

c)      Microwaves are electromagnetic radiation, X-rays are bits of atoms produced in atomic reactions

d)     Microwaves affect organic tissue but all life is completely immune to X-rays

3)      Why is the Lorentz contraction idea an unsatisfactory hypothesis?

a)      Because it was proven wrong

b)      Because it contradicted Newton’s equations

c)      Because it contradicted Maxwell’s equations

d)     Because it had no goal or consequence other than hiding the ether from observation: it was unfalsifiable

4)      When you drop a stone in a pond a wave spreads form the point where the stone was dropped. On the other hand, if you look at the leaves floating on the pond,

a)      They move away being carried by the wave

b)      They are attracted to the point where you dropped the stone

c)      They stay in place bobbing up and down: the wave spreads carrying energy, but does not carry water or leaves with it.

d)     They immediately sink