resistance and V=IR

Question 1

what is the formula linking potential difference and current

Answer 1

potential difference = current x resistance

Question 2

what is the products of an ammeter

Answer 2

measured in amps
flows through the test wire
must always be placed in series with whatever you are investigating

Question 3

what are the products of a voltmeter

Answer 3

measures the potential difference across the test wire (in volts)
must always be placed in parallel around what you are investigating