If a jeweler was trying to sell you a bracelet that he said was 50% copper and 50% gold, how could you be sure he was correct? explain your answer. ()

This is about "assaying" metals. It's what Archimedes was working on in the "Eureka" time.

You'd want the density of the item. It'sd volume could be found by water displacement in a Eureka tin. (It's got an overflow spout for displaced water).

Then it's the mass. This is the weight divided by gravity.

Mass/volume is density. The thing should have a density between that of copper and that of gold. Exactly how much is calculable ... Archimedes said so !!!

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27