Teaching Physics with the Physics Suite
Edward F. Redish
|In the figure at the right is shown a schematic diagram of a circuit consisting of a battery, 3 identical bulbs, and a switch. Assume that the battery is perfect (has no internal resistance) and the connecting wires are ideal (they have no resistance). In addition, you have an ideal ammeter, and an ideal voltmeter. The resistors are labeled R1, R2, and R3. In addition, two contact points are marked in the circuit and labeled 1 and 2.
For each of the cases (a)-(f) below, assume you are starting from the configuration shown but with the switch closed and then perform the action described. Complete the sentence by selecting one of the following letters that describes how the indicated quantity changes: increases (I), remains the same (S), decreases but does not go to zero (D), becomes zero (0).
Note to the instructor: Students are often deeply confused about ammeters and voltmeters. Instead of seeing them as devices with physical properties, they may see them as "ideal and abstract" measuring devices, that is, whereever they are placed, they measure the current and voltage. Thinking through the cases of "incorrectly" attached ammeters and voltmeters sometimes helps.
Not finding what you wanted? Check the Site Map for more information.
Page last modified March 15, 2006: E18