When you connect an unknown resistor across the terminals of a 1.50 V AAA battery having negligible internal resistance, you measure a current of 17.1 mA flowing through it.
A. What is the resistance of this resistor?
B. If you now place the resistor across the terminals of a 12.9 V car battery having no internal resistance, how much current will flow?
C. You now put the resistor across the terminals of an unknown battery of negligible internal resistance and measure a current of 0.456 A flowing through it. What is the potential difference across the terminals of the battery?

(a). The resistance of this resistor is 87.72 Ω.

(b). The current is 0.147 A.

(c). The  potential difference across the terminals of the battery is 40 volt.

Explanation:

Given that,

Voltage = 1.50 V

Current = 17.1 mA

(a). We need to calculate the resistance of this resistor

Using ohm's law

Put the value into the formula

(b). If you now place the resistor across the terminals of a 12.9 V car battery having no internal resistance,

We need to calculate the current

Using ohm's law

Put the value into the formula

(c). The resistor across the terminals of an unknown battery of negligible internal resistance and measure a current of 0.456 A flowing through it.

We need to calculate the potential difference across the terminals of the battery

Using formula of potential difference

Put the value into the formula

Hence, (a). The resistance of this resistor is 87.72 Ω.

(b). The current is 0.147 A.

(c). The  potential difference across the terminals of the battery is 40 volt.

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y