Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 20: Q2Q (page 851)

An electron is moving with a speed v in the plane of the page (Figure 20.81), and there is a uniform magnetic field Binto the page throughout this region; the magnetic field is produced by some large coils that are not shown. Draw the trajectory of the electron, and explain qualitatively.

Short Answer

Expert verified

The trajectory of the electron is as follows:

Step by step solution

01

Given data

Speed of the electron isv .

Magnetic field in the region isB .

02

Magnetic force

Magnetic force on a moving charge is the product of the magnitude of the charge and the cross product of the velocity vector and the magnetic field.

03

Determination of the trajectory of the electron

The cross product of the velocity and the magnetic field will be on the plane of the paper perpendicular to the velocity. As the particle turns due to this force, the direction of force turns too. The particle thus follows a circular path on the plane. Since the charge of the electron is negative, the circle will be clockwise. The trajectory will be as follows:

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

A copper wire with square cross section carries a conventional current I to the left (as in Figure 20.83). There is a magnetic field B perpendicular to the wire. Describe the direction of E⊥, the transverse electric field inside the wire due to the Hall effect, and explain briefly.

A neutral iron bar is dragged to the left at speed v through a region with a magnetic field B points out of the page (Figure 20.122). Which diagram (1-5) best shows the state of the bar?

Calculate the mobile electron density for nickel. A mole of nickel has a mass of 59g (0.059kg), and one mobile electron is released by each atom in metallic nickel. The density of nickel is about 8.8g/cm3, or8.8×103kg/m3

In Figure 20.115 two long straight wires carrying a large conventional current I are connected by one-and-a-quarter turns of wire of radius R. An electron is moving to the right with speed v at the instant that it passes through the center of the arc. You apply an electric field E→at the center of the arc in such a way that the net force on the electron at this instant is zero. (You can neglect the gravitational force on the electron, which is easily shown to be negligible, and the magnetic field of the coil is much larger than the magnetic field of the Earth.)

Determine the direction and magnitude of the electric field . Be sure to explain your work fully; draw and label any vectors you use.

We will consider the possibility that a free electron acted on by an electric field could gain enough energy to ionize an air molecule in a collision. (a) Consider an electron that starts from rest in a region where there is an electric field (due to some charged objects nearby) whose magnitude is nearly constant. If the electron travels a distance dand the magnitude of the electric field isE,what isthe potential difference through which the electron travels? (Pay attention to signs: Is the electron traveling with the electric field or opposite to the electric field?) (b) What is the change in potential energy of the system in this process? (c) What is the change in the kinetic energy of the electron in this process? (d) We found the mean free path of an electron in air to be about 5×10-7 m, and in the previous question you calculated the energy required to knock an electron out of an atom. What is the magnitude of the electric field that would be required in order for an electron to gain sufficient kinetic energy to ionize a nitrogen molecule? (e) The electric field required to cause a spark in air is observed to be about 3×106 V/mat STP. What is the ratio of the magnitude of the field you calculated in the previous part to the observed value at STP? (f) What is it reasonable to conclude about this model of how air becomes ionized? (1) Since we used accurate numbers, this is a huge discrepancy, and the model is wrong. (2) Considering the approximations we made, this is pretty good agreement, and the model may be correct.
See all solutions

Recommended explanations on Physics Textbooks

Nuclear Physics

Read Explanation

Electrostatics

Read Explanation

Electricity

Read Explanation

Rotational Dynamics

Read Explanation

Kinematics Physics

Read Explanation

Quantum 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