Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 18: Problem 77

A galvanometer has a coil resistance of \(34.0 \Omega .\) It is to be made into a voltmeter with a full-scale deflection equal to \(100.0 \mathrm{V}\). If the galvanometer deflects full scale for a current of \(0.120 \mathrm{mA},\) what size resistor should be placed in series with the galvanometer?

Short Answer

Expert verified
Answer: The size of the resistor should be approximately 833299.33 Ω.

Step by step solution

01

Determine the current needed for full-scale deflection

The current required to deflect the galvanometer full scale is given as \(0.120 \mathrm{mA}\). Let's convert it to Amperes to be consistent with the unit: \(0.120 \mathrm{mA} = 0.000120 \mathrm{A}\).
02

Calculate the total resistance of the voltmeter

Using Ohm's Law, we can calculate the total resistance needed for the voltmeter to have a full-scale deflection equal to \(100.0 \mathrm{V}\): \(V = IR\) \(R_{total} = \frac{V}{I}\) Plug in the values: \(R_{total} = \frac{100.0 \mathrm{V}}{0.000120 \mathrm{A}}\) \(R_{total} = 833333.33 \Omega\)
03

Calculate the size of the resistor to be placed in series with the galvanometer

Now, we have the total resistance needed, and we know the coil resistance of the galvanometer. The resistor required in series should bring the total resistance to the required value, so we just subtract the galvanometer's coil resistance from the total resistance: \(R_{resistor} = R_{total} - R_{coil}\) \(R_{resistor} = 833333.33 \Omega - 34.0 \Omega\) \(R_{resistor} = 833299.33 \Omega\) The size of the resistor to be placed in series with the galvanometer should be approximately \(833299.33 \Omega\).

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

What is the energy stored in a small battery if it can move \(675 \mathrm{C}\) through a potential difference of \(1.20 \mathrm{V} ?\)
Show that \(A^{2} \times \Omega=W\) (amperes squared times ohms \(=\) watts).
A parallel plate capacitor is constructed from two square conducting plates of length \(L=0.10 \mathrm{m}\) on a side. There is air between the plates, which are separated by a distance \(d=89 \mu \mathrm{m} .\) The capacitor is connected to a \(10.0-\mathrm{V}\) battery. (a) After the capacitor is fully charged, what is the charge on the upper plate? (b) The battery is disconnected from the plates and the capacitor is discharged through a resistor \(R=0.100 \mathrm{M} \Omega .\) Sketch the current through the resistor as a function of time \(t(t=0\) corresponds to the time when \(R\) is connected to the capacitor). (c) How much energy is dissipated in \(R\) over the whole discharging process?
Capacitors are used in many applications where one needs to supply a short burst of relatively large current. A 100.0 - \(\mu\) F capacitor in an electronic flash lamp supplies a burst of current that dissipates \(20.0 \mathrm{J}\) of energy (as light and heat) in the lamp. (a) To what potential difference must the capacitor initially be charged? (b) What is its initial charge? (c) Approximately what is the resistance of the lamp if the current reaches \(5.0 \%\) of its original value in $2.0 \mathrm{ms} ?$
A current of \(10.0 \mathrm{A}\) is carried by a copper wire of diameter $1.00 \mathrm{mm} .\( If the density of the conduction electrons is \)8.47 \times 10^{28} \mathrm{m}^{-3},$ how long does it take for a conduction electron to move \(1.00 \mathrm{m}\) along the wire?
See all solutions

Recommended explanations on Physics Textbooks

Atoms and Radioactivity

Read Explanation

Nuclear Physics

Read Explanation

Famous Physicists

Read Explanation

Scientific Method Physics

Read Explanation

Engineering Physics

Read Explanation

Fundamentals of Physics

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