People who do very detailed work close up, such as jewellers, often can see objects clearly at much closer distance than the normal 25.0 cm. What is the power of the eyes of a woman who can see an object clearly at a distance of only 9.75 cm? Assume a distance from the eye lens to the retina of 2.00 cm. Number diopters What is the size of the image of a 2.00 mm object, such as lettering inside a ring, held at this distance? Enter your answer as a positive number if the image is upright, and negative if it is inverted. Number mmWhat would the size of the image be if the object were held at the normal 25.0 cm? Number mm

a)    P = 60.26 diopter ,  b)   h´ = -0.4 mm ,  c)   h´ = -0.16 mm

Explanation:

a)  For this exercise we use the equation for thin lenses

               1 / f = 1 / p + 1 / q

where f is the focal length, p the distance to the object and q the distance to the image

in this case q is the distance from the lens to the retina q = 2.00 cm

the distance p is the distance from the object to the lens p = 9.75 cm

               1 / f = 1 / 9.75 + 1/2

               1 / f = 0.6026 cm⁻¹

power is the inverse of the focal length in meters

              P = 1 / f [m]

              P = 0.6026 102

              P = 60.26 diopter

b)  the size of the image

             m = - p / q

             m = - 2 / 9.75

             m = -0.2 X

if we assume that the object is right

            m = h´ / h

            h´ = m h

            h´ = -0.2 2

            h´ = -0.4 mm

if the height of the object h is straight the image and inverted

c) if the object were at p = 25.0 cm

           m = - 2/25

           m = -0.08

             h´ = -0.08 2

             h´ = -0.16 mm

the image would be much smaller

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.

real, smaller and upside-down.   so the answer should be b.