Consider an experiment using a high energy beam from a nd: yag laser, specifically the 3rd harmonic (uv light) output at 355 nm. the pulse energy is 150 mj, the pulse duration is 7 ns, and the repetition rate is 10 hz (meaning the laser "fires" 10 times per second at equal spacings).

a) what is the peak power of the laser? (peak power refers to the power during the time the pulse is on.)

b) what is the average power of the laser? (over many pulses, e. g. over 1 second.)

c) the linewidth of a laser refers to the wavelength range that contains the light. (lasers are nearly "pure colors" which would mean a linedwidth of zero, but in fact they have a finite non-zero linewidth.) assume the linewidth of the laser in this problem is 0.02 nm, and that the beam has an area of 0.3 cm2. the spectral intensity refers to the (peak) power per area per wavelength (where wavelength refers to the wavelength range containing the light, so for a laser it is the linewidth.)
-compute the spectral brightness of the laser pulses in (w/cm2/nm).

d) assume the laser is perfectly linearly polarized and that a polarizer is positioned in the beam path. the polarizer is rotated to reject light going through it. the polarizer has an extinction ratio of 10,000, meaning that it "leaks" 1/10,000 of the light power in its null position. for a single pulse, how much energy is transmitted through the polarizer?

elly's long hair:

a. if the salon only takes cash, then this isn't the problem. it doesn't matter how much she has in her checking account.   she can't get a haircut until she has the cash.

b. if she has overdraft protection, then there's no problem.   she can go ahead and write a check that her account can't cover, then sometime later, pay the bank some outrageous usury for loaning her a few bucks for a few days, but with beautiful hair.

c. if elly has some principles, and doesn't want to write a bad check, then now she has a problem.   her desire for the new hairstyle is in conflict with her honesty and integrity.

d.   if the bank will not process a check she writes, then even if she had a million $$ in her account, she couldn't use any of it.   the amount she has in her account is not the problem.   and if i may suggest, she might as well close her checking account, and put the money where it'll work for her.   it's not doing her a bit of good in a checking account, since she can't write any checks.

justin can't pay the full balance:

a. he can't even handle the credit limit he has now.   under no circumstances should he ask for a higher limit.

b.   he can ask for the grace period to be extended.   but that's no solution, the bank will almost certainly refuse anyway, and there are much better options.   he knew the rules of his credit card when he started using it.

c.   he definitely should pay the interest on the balance, plus as much of the balance as he can cover at the same time.

d.   he definitely should pay the minimum otherwise they could shut down his card.   he should also pay as much more as he possibly can.   he should also remember the awkward situation he's in, stop buying stuff on credit that he can't afford, and avoid adding any more debt.

i'd say that justin's best best option isn't on this list of choices.   what he has to do:   pay as much as he can at least the minimum payment plus as much more as he can and then avoid adding more debt.