There are two categories of ultraviolet light. Ultraviolet A (UVA) has a wavelength ranging from 320 nm to 400 nm. It is necessary for the production of vitamin D. UVB, with a wavelength in vacuum between 280 nm and 320 nm, is more dangerous because it is much more likely to cause skin cancer. (a) find the frequency ranges of UVA and UVB.

(b) what are the ranges of the wave numbers for UVA and UVB?

(a) UVA - frequency range: 7.5*10^14 Hz to 9.37*10^14 Hz

    UVB - frequency range: 9.37*10^14Hz to 1.07*10^15Hz

(b) UVA - wavenumber range: 1.57*10^7 m^-1 to 1.96*10^7m^-1

    UVB - wavenumber range: 1.97*10^7 m^-1 to 2.24*10^7m^-1

Explanation:

In order to calculate the frequency ranges fro the two categories of ultraviolet light, you use the following formula:

            (1)

f: frequency

c: speed of light in vacuum = 3*10^8 m/s

λ: wavelength

(a) For UVA the wavelength range is λ1 = 320nm to λ2 = 400nm.

The frequency range is:

frequency range: 7.5*10^14 Hz to 9.37*10^14 Hz

For UVB the wavelength range is λ1 = 280nm  to λ2 = 320nm.

The frequency range is:

frequency range: 9.37*10^14Hz to 1.07*10^15Hz

(b) The ranges for the wavenumbers are:

UVA:

wavenumber range: 1.57*10^7 m^-1 to 1.96*10^7m^-1

UVB:

wavenumber range: 1.97*10^7 m^-1 to 2.24*10^7m^-1

- measure reactants precisely. ( first choice)

- stir to the reaction take place. ( second choice)

- wait patiently until the reaction completes. ( fourth choice)

- make sure to recover as much copper as possible. ( last choice)

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.