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Table
of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
from
Popular Electronics,
published October 1954 - April 1985. All copyrights are hereby acknowledged.
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If terms like "magnetostriction,"
"mu-metal," and "D-ring"
arouse your technostimulus receptors, then this quiz on Magnetic Phenomena should
be just what you've been waiting for. It appeared in a 1962 edition of Popular
Electronics, but the principles therein have not changed since then. I
must admit that I had never given thought to the orientation in which bar magnets
should be stored when in close proximity to each other, especially since trying
to store them the "wrong" way results in them trying to reconfigure themselves
to the "right" way automatically. Not mentioned here is that a soft iron or
other ferrous metal should be placed across the ends to help concentrate the
magnetic fields within the magnets, thereby reducing the possibility of demagnetization
due to nearby objects.
Magnetic Phenomena Quiz
By Robert P. Balin
Neither magnets nor magnetism are mysteries to the experimenter. But this
quiz will test your knowledge of the basic principles of magnetic phenomena.
Mark each statement "True" or "False" and check your answers at the bottom.
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1 - The north pole of a compass points to the earth's north magnetic pole.
TRUE or FALSE?
2 - If the separation between two unlike magnetic poles is reduced by half,
the attraction between them will become four times as great.
TRUE or FALSE?
3 - If a compass is placed beneath a wire passing electrons from A to B,
its north pole will point to the right.
TRUE or FALSE?
4 - Bar magnets should be stored by placing them so that like poles are
side by side.
TRUE or FALSE?
5 - There is no insulator for magnetic fields. Some metals simply offer
more resistance to magnetism than others.
TRUE or FALSE?
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6 - A "D-ring" is usually found on d.c. electromagnetic relay coils.
TRUE or FALSE?
7 - When a nickel-iron rod is magnetized, it will grow shorter in length.
TRUE or FALSE?
8 - The electromagnet shown here will have its north pole located at the
top of the coil.
TRUE or FALSE?
9 - An electron passing through the deflection yoke magnetic field and
out of the page will be deflected to the right.
TRUE or FALSE?
10 - A "keeper" is placed across the poles of a horseshoe magnet to prevent
the magnet's field from passing through nearby ferrous objects.
TRUE or FALSE?
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See answers below.
Quizzes from vintage electronics magazines such as Popular
Electronics, Electronics-World, QST,
Radio-Electronics, and Radio News
were published over the years - some really simple and others not so simple. Robert P. Balin
created most of the quizzes for Popular Electronics. This is a listing
of all I have posted thus far.
- RF Cafe Quiz #71:
Tech Headlines for Week of 3/13/2023
- RF Cafe Quiz #70:
Analog &
RF Filter Basics
- RF Cafe Quiz #69:
RF
Electronics Basics
- RF Cafe Quiz #68:
RF & Analog Company Mergers & Acquisitions in 2017
- RF Cafe Quiz #67:
RF & Microwave Company Name Change History
- RF Cafe Quiz #66:
Spectrum and Network Measurements
- RF Cafe Quiz #65:
Troubleshooting & Repairing Commercial Electrical Equipment
- RF Cafe Quiz #64:
Space-Time Adaptive Processing for Radar
- RF Cafe Quiz #63:
Envelope Tracking Power Amplifiers
- RF Cafe Quiz #62:
Stimson's Introduction to Airborne Radar
- RF Cafe Quiz #61:
Practical Microwave Circuits
- RF Cafe Quiz #60:
Ten Essential Skills for Electrical Engineers
- RF Cafe Quiz #59:
Microwave Circulator Design
- RF Cafe Quiz #58:
Microwave and Millimeter-Wave Electronic Packaging
- RF Cafe Quiz #57:
Frequency-Agile Antennas for Wireless Communications
- RF Cafe Quiz #56:
Tube Testers
and Electron Tube Equipment
- RF Cafe Quiz #55:
Conquer
Radio Frequency
- RF Cafe Quiz #54:
Microwave Mixer Technology and Applications
- RF Cafe Quiz #53:
Chipless RFID Reader Architecture
- RF Cafe Quiz #52:
RF and Microwave Power Amplifiers
- RF Cafe Quiz #51:
Antennas and Site Engineering for Mobile Radio Networks
- RF Cafe Quiz #50:
Microstrip Lines and Slotlines
- RF Cafe Quiz #49:
High-Frequency Integrated Circuits
- RF Cafe Quiz #48:
Introduction to Infrared and Electro-Optical Systems
- RF Cafe Quiz #47:
LCP for Microwave Packages and Modules
- RF Cafe Quiz #46:
RF, Microwave, and Millimeter-Wave Components
- RF Cafe Quiz #45:
Dielectric and Thermal Properties of Materials at Microwave Frequencies
- RF Cafe Quiz #44:
Monopulse Principles and Techniques
- RF Cafe Quiz #43:
Plasma Antennas
- RF Cafe Quiz #42: The Micro-Doppler
Effect in Radar
- RF Cafe Quiz #41: Introduction
to RF Design Using EM Simulators
- RF Cafe Quiz #40: Introduction
to Antenna Analysis Using EM Simulation
- RF Cafe Quiz #39: Emerging
Wireless Technologies and the Future Mobile Internet
- RF Cafe Quiz #38: Klystrons,
Traveling Wave Tubes, Magnetrons, Crossed-Field Amplifiers, and Gyrotrons
- RF Cafe Quiz #37: Component
Reliability for Electronic Systems
- RF Cafe Quiz #36: Advanced
RF MEMS
- RF Cafe Quiz #35: Frequency
Synthesizers: Concept to Product
- RF Cafe Quiz #34: Multi-Gigabit
Microwave and Millimeter-Wave Wireless Communications
- RF Cafe Quiz #33: Battlespace
Technologies: Network-Enabled Information Dominance
- RF Cafe Quiz #32: Modern Communications
Receiver Design and Technology
- RF Cafe Quiz #31: Quantum
Mechanics of Nanostructures
- RF Cafe Quiz #30: OFDMA System
Analysis and Design
- RF Cafe Quiz #29: Cognitive
Radar
- RF Cafe Quiz #28: Human-Centered
Information Fusion
- RF Cafe Quiz #27: Remarkable
Engineers
- RF Cafe Quiz #26: Substrate
Noise Coupling in Analog/RF Circuits
- RF Cafe Quiz #25: Component
Reliability for Electronic Systems
- RF Cafe Quiz #24: Ultra Low
Power Bioelectronics
- RF Cafe Quiz #23: Digital
Communications Basics
- RF Cafe Quiz #22: Remember
the Basics?
- RF Cafe Quiz #21: Wireless
Standards Knowledge
- RF Cafe Quiz #20: Famous First
Names
- RF Cafe Quiz #19: Basic Circuit
Theory
- RF Cafe Quiz #18: Archaic
Scientific Words & Definitions
- RF Cafe Quiz #17: Inventors &
Their Inventions
- RF Cafe Quiz #16: Antennas
- RF Cafe Quiz #15: Numerical
Constants
- RF Cafe Quiz #14: Oscillators
- RF Cafe Quiz #13: General
Knowledge
- RF Cafe Quiz #12: Electronics
Corporations Headquarters
- RF Cafe Quiz #11: Famous Inventors &
Scientists
- RF Cafe Quiz #10: A Sampling
of RF & Wireless Topics
- RF Cafe Quiz #9: A Smorgasbord
of RF Topics
- RF Cafe Quiz #8: Hallmark Decades
in Electronics
- RF Cafe Quiz #7: Radar Fundamentals
- RF Cafe Quiz #6: Wireless Communications
Fundamentals
- RF Cafe Quiz #5: Company Logo
Recognition
- RF Cafe Quiz #4: General RF
Topics
- RF Cafe Quiz #3: General RF/Microwave
Topics
- RF Cafe Quiz #2: General RF
Topics
- RF Cafe Quiz #1: General RF
Knowledge
- Vacuum Tube Quiz,
February 1961 Popular Electronics
- Kool-Keeping Kwiz, June
1970 Popular Electronics
- Find the Brightest
Bulb Quiz, April 1960 Popular Electronics
-
Where Do the Scientists Belong? - Feb 19, 1949 Saturday Evening Post
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What's
Your EQ? - February 1962 Radio-Electronics
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What's
Your EQ? - March 1962 Radio-Electronics
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What's
Your EQ? - July 1961 Radio-Electronics
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What's
Your EQ? - August 1961 Radio-Electronics
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Can You
Name These Strange Electronic Effects? - August 1962 Radio-Electronics
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What's
Your EQ? - September 1961 Radio-Electronics
-
What's
Your EQ? - September 1962 Radio-Electronics
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What's Your EQ? - October 1961 Radio-Electronics
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What's Your EQ? - November 1961 Radio-Electronics
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What's Your EQ? - March 1964 Radio-Electronics
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What's Your EQ? - April 1962 Radio-Electronics
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What's Your EQ? - May 1962 Radio-Electronics
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What's Your EQ? - June 1962 Radio-Electronics
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What's Your EQ? - April 1967 Radio-Electronics
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What's Your EQ? - March 1967 Radio-Electronics
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What's Your EQ? - December 1964 Radio-Electronics
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What's Your EQ? - January 1967 Radio-Electronics
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Wanted: 50,000 Engineers - January 1953 Popular Mechanics
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What's Your EQ? - August 1964 Radio-Electronics
- Voltage Quiz
- December 1961 Popular Electronics
-
What is It? - June 1941 Popular Science
- What Do You Know
About Resistors? - April 1974 Popular Electronics
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What's Your EQ? - September 1963 Radio-Electronics
- Potentiometer Quiz - September
1962 Popular Electronics
-
Mathematical Bafflers - March 1965 Mechanix Illustrated
- Op Amp Quiz -
October 1968 Popular Electronics
- Electronic "A"
Quiz - April 1968 Popular Electronics
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What's Your EQ? - May 1961 Radio-Electronics
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Popular Science Question Bee - February 1939 Popular Science
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What is It? - A Question Bee in Photographs - June 1941 Popular Science
-
What's Your EQ? - June 1961 Radio-Electronics
-
What's Your EQ? - June 1964 Radio-Electronics
-
What's Your EQ? - May 1964 Radio-Electronics
-
What's Your EQ? - August 1963 Radio-Electronics
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What's Your EQ? - May 1963 Radio-Electronics
- Bridge
Function Quiz - September 1969 Radio-Electronics
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What's Your EQ? - March 1963 Radio-Electronics
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What's Your EQ? - February 1967 Radio-Electronics
-
Circuit Quiz - June 1966 Radio-Electronics
-
What's Your EQ? - June 1966 Radio-Electronics
- Electronics
Mathematics Quiz - June 1969 Popular Electronics
- Brightest
Light Quiz - April 1964 Popular Electronics
-
What's Your EQ? - April 1963 Radio-Electronics
- Electronics "B" Quiz
- July 1969 Popular Electronics
- Ohm's Law Quiz
- March 1969 Popular Electronics
-
Antenna Quiz - November 1962 Electronics World
- Color Code Quiz
- November 1967 Popular Electronics
- CapaciQuiz
- August 1961 Popular Electronics
- Transformer
Winding Quiz - December 1964 Popular Electronics
-
Audiophile Quiz - November 1957 Radio-electronics
- Capacitor
Function Quiz - March 1962 Popular Electronics
- Greek Alphabet
Quiz - December 1963 Popular Electronics
- Circuit
Designer's Name Quiz - July 1968 Popular Electronics
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Sawtooth Sticklers Quiz - November 1960 Radio-Electronics
-
Elementary
Radio Quiz - December 1947 Radio-Craft
- Hi-Fi
Quiz - October 1955 Radio & Television News
- Electronics Physics
Quiz - March 1974 Popular Electronics
- A Baffling Quiz
- January 1968 Popular Electronics
- Electronics IQ
Quiz - May 1967 Popular Electronics
- Plug and Jack
Quiz - December 1967 Popular Electronics
- Electronic
Switching Quiz - October 1967 Popular Electronics
- Electronic
Angle Quiz - September 1967 Popular Electronics
- International
Electronics Quiz - July 1967 Popular Electronics
- FM Radio
Quiz - April 1950 Radio & Television News
- Bridge Circuit
Quiz -December 1966 Popular Electronics
- Diode Function
Quiz - August 1965 Popular Electronics
- Diagram Quiz,
August 1966 Popular Electronics
- Quist Quiz - November
1953 QST
- TV Trouble Quiz,
July 1966 Popular Electronics
- Electronics History Quiz,
December 1965 Popular Electronics
- Scope-Trace Quiz,
March 1965 Popular Electronics
-
Electronic
Circuit Analogy Quiz, April 1973
-
Test Your Knowledge of Semiconductors, August 1972 Popular Electronics
- Ganged Switching
Quiz, April 1972 Popular Electronics
- Lamp Brightness
Quiz, January 1969 Popular Electronics
- Lissajous
Pattern Quiz, September 1963 Popular Electronics
- Electronic
Quizoo, October 1962 Popular Electronics
- Electronic
Photo Album Quiz, March 1963 Popular Electronics
- Electronic
Alphabet Quiz, May 1963 Popular Electronics
- Quiz: Resistive?
Inductive? or Capacitive?, October 1960 Popular Electronics
- Vector-Circuit
Matching Quiz, June 1970 Popular Electronics
- Inductance
Quiz, September 1961 Popular Electronics
- RC Circuit Quiz,
June 1963 Popular Electronics
- Diode Quiz, July
1961 Popular Electronics
- Electronic
Curves Quiz, February 1963 Popular Electronics
- Electronic
Numbers Quiz, December 1962 Popular Electronics
- Energy Conversion
Quiz, April 1963 Popular Electronics
- Coil Function
Quiz, June 1962 Popular Electronics
-
Co-Inventors Quiz - January 1965 Electronics World
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"-Tron" Teasers Quiz - October 1963 Electronics World
- Polarity Quiz
- March 1968 Popular Electronics
-
Television
I.Q. Quiz - October 1948 Radio & Television News
- Amplifier Quiz
Part I - February 1964 Popular Electronics
- Semiconductor
Quiz - February 1967 Popular Electronics
- Unknown
Frequency Quiz - September 1965 Popular Electronics
- Electronics
Metals Quiz - October 1964 Popular Electronics
- Electronics
Measurement Quiz - August 1967 Popular Electronics
- Meter-Reading
Quiz, June 1966 Popular Electronics
- Electronic
Geometry Quiz, January 1965 Popular Electronics
- Electronic
Factor Quiz, November 1966 Popular Electronics
- Electronics
Math Quiz, November 1965 Popular Electronics
- Series Circuit
Quiz, May 1966 Popular Electronics
- Electrochemistry
Quiz, March 1966 Popular Electronics
- Biz
Quiz: Test Your Sales Ability - April 1947 Radio News
- Electronic
Analogy Quiz, November 1961 Popular Electronics
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Magnetic Quiz Answers
1 TRUE. The north pole of a compass points to the earth's north magnetic
pole which is actually the south pole of a large magnet inside the earth.
2 TRUE. The force of attraction between unlike magnetic poles varies inversely
as the square of the distance between them.
3 TRUE. The north pole of a compass always indicates the direction of the
magnetic field in which it lies. To determine the direction of the magnetic
field, grasp the wire with your left hand with the thumb in the direction of
electron flow, from A to B. Your fingertips will point in the direction of the
magnetic field.
4 FALSE. Bar magnets should be stored so that opposite poles lie adjacent
to each other. The magnetic field from each bar will then have a closed magnetic
circuit lying entirely within the bars themselves. Hence, the magnetic fields
are least likely to go into nearby metallic objects.
5 TRUE. There are no materials which resist magnetic fields. However, magnetic
shields made of high-permeability materials such as mu-metal are used to bypass
magnetic fields around the devices to be isolated from the effects of the magnetic
fields.
6 FALSE. The D-ring is a shorted turn of copper used on a.c. relay coils
to prevent armature chattering. When the magnetic field set up by the coil starts
to collapse on alternate half cycles, a circulating current in the D-ring builds
up a magnetic field which holds the contacts closed.
7 TRUE. This is the principle of "magnetostriction" used in ultrasonic transducers
for sonar and in ultrasonic cleaning devices.
8 TRUE. Electrons will enter the coil from the bottom and exit at the top
of the coil. Grasp the coil with your left hand with the fingers wrapped in
the direction of the electron flow. Your thumb will point to the north pole.
9 FALSE. Use your left hand to determine the magnetic field around a moving
electron. The thumb points in the direction of electron flow and the curled
fingers point in the direction of its magnetic field. Hence, the electron coming
out of the page will have a clockwise field around it. The magnetic field to
the right of the electron will have the same direction as the field of the deflection
coil. Since magnetic lines which have the same direction repel each other, the
electron experiences a force to the left.
10 TRUE. Almost all of the magnet's magnetic lines of force will pass through
the soft iron bar. The "keeper" is usually employed when storing permanent magnets
in order to preserve the magnetic strength.
Posted March 12, 2021 (updated from original post on 6/12/2013)
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