(See Discussion Question Q25.14.) An ideal ammeter A is placed in a circuit with a battery and a light bulb as shown in Fig. Q25.15a, and the ammeter reading is noted. The circuit is then reconnected as in Fig. Q25.15b, so that the positions of the ammeter and light bulb are reversed. (a) How does the ammeter reading in the situation shown in Fig. Q25.15a compare to the reading in the situation shown in Fig. Q25.15b? Explain your reasoning. (b) In which situation does the light bulb glow more brightly? Explain your reasoning.

Short Answer

Expert verified

(a) The ammeters in both situations have the same readings since the current is the same in both circuits.

(b) The light bulbs glow equally bright since the current is the same in both circuits.

Step by step solution

01

Ohm’s law

The resistance, or the ratio of voltage to current, for all or part of an electric circuit at a fixed temperature, is generally constant.

Ohm's law may be expressed mathematically as

VI=R

Here, V is the voltage, I is the current, and R is the resistor.

02

(a) Determine the current in both circuits:

Let the resistance of the bulb is R .

We know the resistance of an ideal ammeter is 0 .

So, the current through the circuit in both cases will be

I=εR

Here, εis the emf voltage.

Therefore, the ammeters in both situations have the same readings since the current is the same in both circuits.

03

(b) Determine the power dissipation in both circuits

Let the resistance of the bulb is R .

We know the resistance of an ideal ammeter is 0 .

So, the power dissipation in the resistance R is

P=I2R.

Therefore, the light bulbs glow equally bright since the current is the same in both circuits.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The magnetic force on a moving charged particle is always perpendicular to the magnetic fieldB. Is the trajectory of a moving charged particle always perpendicular to the magnetic field lines? Explain your reasoning.

Two coils have mutual inductance M=3.25×10-4H. The current in the first coil increases at a uniform rate of 830 A/S. (a) what is the magnitude of the induced emf in the second coil? Is it constant? (b) Suppose that the current described is in the second coil rather than the first. What is the magnitude of the induced emf in the first coil?

A beam of protons traveling at 1.20 km/s enters a uniform magnetic field, traveling perpendicular to the field. The beam exits the magnetic field, leaving the field in a direction pependicurlar to its original direction (Fig. E27.24). The beam travels a distance of 1.10 cm while in the field. What is the magnitude of the magnetic field?

The heating element of an electric dryer is rated at 4.1 kW when connected to a 240-V line. (a) What is the current in the heating element? Is 12-gauge wire large enough to supply this current? (b) What is the resistance of the dryer’s heating element at its operating temperature? (c) At 11 cents per kWh, how much does it cost per hour to operate the dryer?

Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. These cyclotrons typically accelerate H-(the hydride ion, which has one proton and two electrons) to an energy of 5MeVto20MeV.This ion has a mass very close to that of a proton because the electron mass is negligible about 12000of the proton’s mass. A typical magnetic field in such cyclotrons is 1.9T..(a) What is the speed of a 5.0-MeVH-? (b) If the H-has energy 5.0MeVandB=1.9T what is the radius of this ion’s circulator orbit?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free