In europe the standard voltage in homes is 220 v instead of the 120 v used in the united states. therefore a "100-w" european bulb would be intended for use with a 220-v potential difference (see problem 25.40). (a) if you bring a "100-w" european bulb home to the united states, what should be its u. s. power rating? (b) how much current will the 100-w european bulb draw in normal use in the united states?

a) The US power rating for the european bulb must be 27.27 W

b) The current in the United Stated for the european bulb is 0.227A

Explanation:

First of all the bulb is not going to light in 120V like it does in 220V, the bright is going to be much lower (near 1/4). Now, lets take a look on a circuit perspective:

The bulb in a circuit is modeled like a simple resistor, so we have a resistor conected to a voltage source, see figure 1. There we have a current given by:

Where is the 220v Input voltage, R is the resistance from the bulb. In the problem we have the power consumption in watts given by:

Clearing

Now, from ohm's law

So 484 ohm is the resistance from the bulb.

Now in the circuit lets replace the voltage source from 220v to 120v and lets calculate the current, and the power consuptiom

And the power consuptiom:

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..

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.