1&2 Questions.

[Studyinghard]

Hey

This is regarding electricity.

If 5.0  10 18 electrons per second pass through a current-measuring device, what is
the current in amperes?

Working out aswell thanks

A theory question perhaps:

A student claims that the charge on an ion in a solution is 2.4  10 19 C. Why must
the student be incorrect?

Not sure where the fact is from in the text book but ...
Answer: charge not a whole number

[minilunchbox]

Do you mean electrons?

The charge on a proton is so the charge on one electron is .

Therefore the charge on electrons is .

I=q/t   
q=-0.801C
t=1 sec

I=-0.801/1
=-0.801A

[Studyinghard]

Another question, just having trouble understanding.

Resistance is the quantity that affects the fl ow of current in a circuit. For a
given potential difference at the source a small, circuit resistance means a
high current, and a large, circuit resistance means a small current.

Thats the definition from a textbook. So in other words is that just saying..

For a specific amount of voltage, small resistance means high current and high resistance means small current

[Edmund]

Another question, just having trouble understanding.

Resistance is the quantity that affects the fl ow of current in a circuit. For a
given potential difference at the source a small, circuit resistance means a
high current, and a large, circuit resistance means a small current.

Thats the definition from a textbook. So in other words is that just saying..

For a specific amount of voltage, small resistance means high current and high resistance means small current

Look at it this way:

Resistance is a measure of how hard it is to move charge (amount of charge is voltage) around a circuit.

Current is the flow of charge around the circuit and it is affected by the Voltage (higher voltage means more charge which means higher flow of charge so higher current) and Resistance (higher resistance means harder to move charge therefore smaller current). Therefore we can express current this way:



where Current is directly proportional to Voltage and inversely proportional to resistance.