Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 4: Q29E (page 843)

When switch Sin Fig. E25.29 is open, the voltmeter V reads 3.08 V. When the switch is closed, the voltmeter reading drops to 2.97 V, and the ammeter A reads 1.65 A. Find the emf, the internal resistance of the battery, and the circuit resistance R. Assume that the two meters are ideal, so they don’t affect the circuit.

Fig. E25.29.

Short Answer

Expert verified
  1. The emf of the battery is 3.08 V.
  2. The internal resistance of the battery is0.067Ω.
  3. The circuit resistance R is 1.80Ω.

Step by step solution

01

Determination of the emf when the circuit is open.

When the switch is open, the circuit is incomplete, and therefore no current flows as shown in the figure below.

So, l = 0

The voltage drop across the circuit is

Vab=ε=3.08V

02

Determination of the emf when the circuit is closed, internal resistance and circuit resistance.

When the switch is closed, the circuit is complete and therefore current will flow as shown in figure below,

VoltagedropVab=ε-lrThevalueofVabgivenis2.97VSolveforrandsubstituteallthevalues,r=ε-Vabl=3.08V-2.97V1.65A=0.067Ω

For, circuit resistance, according to Ohm’s law,

V=lRR=Vabl=2.97V1.65A=1.80ΩThus,theinternalresistanceandthecircuitresistanceare0.067Ωand1.80Ωrespectively.

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.

Start your free trial

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

Questions: A conductor that carries a net charge has a hollow, empty cavity in its interior. Does the potential vary from point to point within the material of the conductor? What about within the cavity? How does the potential inside the cavity compare to the potential within the material of the conductor?

A silver wire 2.6 mm in diameter transfers a charge of 420 C in 80

min. Silver containsfree electrons per cubic meter. (a) What is the

current in the wire? (b) What is the magnitude of thedrift velocity of the

electrons in the wire?

A typical small flashlight contains two batteries, each having an emf of1.5V, connected in series with a bulb having resistance17Ω. (a) If the internal resistance of the batteries is negligible, what power is delivered to the bulb? (b) If the batteries last for1.5hwhat is the total energy delivered to the bulb? (c) The resistance of real batteries increases as they run down. If the initial internal resistance is negligible, what is the combined internal resistance of both batteries when the power to the bulb has decreased to half its initial value? (Assume that the resistance of the bulb is constant. Actually, it will change somewhat when the current through the filament changes, because this changes the temperature of the filament and hence the resistivity of the filament wire.)

Ordinary household electric lines in North America usually operate at 120 V . Why is this a desirable voltage, rather than a value considerably larger or smaller? On the other hand, automobiles usually have 12 V electrical systems. Why is this a desirable voltage?

A heart defibrillator is used to enable the heart to start beating if it has stopped. This is done by passing a large current of12Athrough the body at25Vfor a very short time, usually3.0msabout . (a) What power does the defibrillator deliver to the body, and (b) how much energy is transferred ?
See all solutions

Recommended explanations on Physics Textbooks

Scientific Method Physics

Read Explanation

Atoms and Radioactivity

Read Explanation

Conservation of Energy and Momentum

Read Explanation

Magnetism and Electromagnetic Induction

Read Explanation

Physical Quantities And Units

Read Explanation

Torque and Rotational Motion

Read Explanation
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