A circuit you’re building needs an ammeter that goes from 0 mA to a full-scale reading of 50.0 mA. Unfortunately, the only ammeter in the storeroom goes from 0 μA to a full-scale reading of only 500 μA. Fortunately, you can make this ammeter work by putting it in a measuring circuit, as shown in Figure P23.66. This lets a certain fraction of the current pass through the meter; knowing this value, you can deduce the total current. Assume that the ammeter is ideal.
a. What value of R must you use so that the meter will go to full scale when the current I is 50.0 mA?
Hint: When I = 50.0 mA, the ammeter should be reading its maximum value.
b. What is the equivalent resistance of your measuring circuit?
Figure P23.66
Want to see the full answer?
Check out a sample textbook solutionChapter 23 Solutions
College Physics: A Strategic Approach (4th Edition)
Additional Science Textbook Solutions
University Physics (14th Edition)
An Introduction to Thermal Physics
Tutorials in Introductory Physics
The Cosmic Perspective
University Physics Volume 1
Conceptual Integrated Science
- Calculate the equivalent resistance between points P and Q of the electrical network shown in Figure P29.80.arrow_forwardA battery with = 6.00 V and no internal resistance supplies current to the circuit shown in Figure P27.9. When the double-throw switch S is open as shown in the figure, the current in the battery is 1.00 mA. When the switch is closed in position a, the current in the battery is 1.20 mA. When the switch is closed in position b, the current in the battery is 2.00 mA. Find the resistances (a) R1, (b) R2, and (c) R3. Figure P27.9 Problems 9 and 10.arrow_forwardTaking R = 1.00 k and = 250 V in Figure P21.49, determine the direction and magnitude of the current in the horizontal wire between a and e. Figure P21.49arrow_forward
- (a) Can the circuit shown in Figure P18.29 be reduced to a single resistor connected to the batteries? Explain. (b) Find the magnitude of the current and its direction in each resistor. Figure P18.29arrow_forwardIf the terminals of a battery with zero internal resistance are connected across two identical resistors in series, the total power delivered by the battery is 8.00 W. If the same battery is connected across the same resistors in parallel, what is the total power delivered by the battery? (a) 16.0 W (b) 32.0 W (c) 2.00 W (d) 4.00 W (e) none of those answersarrow_forwardConsider a resistor made of copper that you connect to a 12.0 V power supply in an oven where the temperature is 300°C. In this heat, you find that a current of 2.00 A goes through the resistor. Determine the current that goes through this resistor if you connect it to the same power supply but this time on the surface of Mars where the temperature is about -100°C.arrow_forward
- (a) Three 8.70 Q resistors are connected in series to a 16.0 V battery. What is the equivalent resistance (in Q) of the circuit? What is the current (in A) in each resistor? (b) Three other 8.70 Q resistors are all connected in parallel across a second 16.0 V battery. What is the equivalent resistance (in Q) of this circuit? What is the current (in A) in each resistor in this circuit? Aarrow_forwardA defibrillator sends a 6.75 A current through the chest of a patient by applying a 9500 V voltage as in the figure. What is the resistance of the path in kΩ?arrow_forwardThe brightness of a lightbulb is dependent on the current that goes through the lightbulb (in reality on the power, which is I^2/R). In Europe, the voltage used is 220 Volts, as opposed to the 120 Volts used in the USA. Will a lighbulb that is made for European voltage work well or poorly in the USA? It will work poorly in the USA. Since I=V/R, if V decreases, so does I, and so does the brightness. It will work more efficiently in the USA. Since I=V/R, if V decreases, I increases, and the brightness increases. It will work better in the USA because the resistance of the wires is smaller. Whether it works better or worse depends on how modern the wiring system is, regardless of the voltage, V.arrow_forward
- You have a string of holiday lights, consisting of 30 bulbs in series. The string of lights is plugged into a wall socket, which we can assume to supply a voltage of 120 V. There is also a fuse in series with the light bulbs. The fuse is designed to blow (this means the current cannot flow anymore) if the current is greater than or equal to 3.0 A; however, with 30 bulbs the current is only 2.50 A. If a bulb in the string burns out, what happens is that a short circuit is formed that allows the current to bypass the burned-out bulb. The short circuit is a path of negligible resistance, in parallel with the burned-out bulb. This allows the remaining lights to stay on, but at the expense of increasing the current in the circuit, and increasing the chance that more bulbs will burn out. One of the purposes of the fuse is to prevent all the bulbs from burning out. (a) If one bulb burns out, so the string goes from having 30 bulbs in series to 29 bulbs in series, by how much will the current…arrow_forwardThe 400 V battery of a Tesla Model S electric car stores 3.0 X 108 J of energy. At 65 mph, the car can drive 250 miles before the battery is depleted. At this speed, what is the current delivered by the battery?arrow_forward(a) Three 2.40 Q resistors are connected in series to a 22.0 V battery. What is the equivalent resistance (in 0) of the circuit? What is the current (in A) in each resistor? A (b) Three other 2.40 Q resistors are all connected in parallel across a second 22.0 V battery. What is the equivalent resistance (in 0) of this circuit? What is the current (in A) in each resistor in this circuit? Aarrow_forward
- Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning