A partially completed schematic of a simple direct-current circuit is shown below in…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
A partially completed schematic of a simple direct-current circuit is shown below in textual description.
• A battery with its positive terminal on the left and negative terminal on the right is connected to a horizontal conducting wire that leads to an unconnected gap labeled Point P.
• From Point P a vertical conductor drops downward to an unconnected gap labeled Point Q.
• A horizontal conducting wire returns from Point Q to the negative terminal of the battery, completing a rectangular path except for the two gaps.
You have the following components available, each represented by its schematic symbol: a resistor, a switch, an ammeter, and a voltmeter. The goal is to modify the circuit so that when the switch is closed the resistor operates at its rated power and the current through it is measured correctly without altering that current. The potential difference across the resistor must also be measurable without diverting additional current through the resistor.
Answer the following questions.
(1) Indicate which component should be placed between Points P and Q to control whether the circuit is open or closed. Justify your choice with reference to the electrical behavior of the component.
(2) Show where and how the remaining three components should be incorporated so that the measurement requirements stated in the prompt are satisfied. Describe fully the series or parallel relationships you establish.
(3) A common mistake is to place the ammeter in parallel with the resistor instead of in series. Explain quantitatively how this error would affect the measured current and the resistor’s operating conditions, assuming the ammeter has negligible resistance.