Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes App Notes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Stencils for Visio RF & EE Shapes for Word Advertising RF Cafe Homepage Thank you for visiting RF Cafe!
Anatech Electronics

Dielectric and Thermal Properties
of Materials at Microwave Frequencies
RF Cafe Quiz #45

RF Engineering Quizzes - RF CafeAll RF Cafe Quizzes make great fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job.

Click here for the complete list of RF Cafe Quizzes.

Note: Some material based on books have quoted passages.

 

Handbook of Dielectric and Thermal Properties of Materials at Microwave Frequencies - RF Cafe Featured BookThis quiz is based on the information presented in Handbook of Dielectric and Thermal Properties of Materials at Microwave Frequencies, by Theodore Anderson. This book is a wealth of information of dielectric characteristics of biological tissues in plants, animals, as well as for ceramics, soils and minerals. Particular attention is paid to properties in the ISM frequency bands. Extensive sources for similar studies are provided.

 

 

Also consider: USAFSAM-TR-85-73, Radiofrequency Radiation Dosimetry Handbook (4th Edition)

This is the mother of all such references for SAR studies.

 

 

1.  What is a serious reason for uneven distribution of the thermal field in lossy media?

a)  Lossiness

b)  Temperature gradients

c)  Thermal runaway

d)  Impurities

 

 

2.  What is the mechanism for generating heat in dielectric materials via microwaves?

a)  Dipole polarization where polar molecules try to align themselves with the applied field

b)  High internal friction

c)  High temperature gradients

d)  Atomic molecularity

 

 

3.  What name is given to a resonant cavity method for measuring complex dielectric permittivity of lossy materials?

a)  Spatial injection method

b)  Surface current method

c)  Skin effect method

d)  Perturbation method

 

 

4.  What does heat capacity of a material measure?

a)  Ability to accumulate heat by increasing its temperature

b)  Amount of heat contained

c)  Absolute temperature

d)  Relative temperature

 

 

5.  What are the main mechanisms for interaction between EM waves and biological (e.g., brain) tissue?

a)  Oscillation of polar water molecules and ions

b)  Radiation of conductive salts

c)  Conduction of mineral impurities

d)  All the above

 

 

6.  Which list represents materials ordered from least to most polar high frequency dielectric properties.a)  PVC, rubber, polyethylene

b)  Rubber, PVC, polyethylene

c)  Polyethylene, rubber, PVC

d)  All have equal polar properties at high frequency

 

 

7.  Which property is very important in affecting temperature distribution in liquids heated by microwaves?

a)  Density

b)  Conductivity

c)  Dielectric constant

d)  Viscosity

 

 

8.  Which body component has the highest conductivity in the 915 MHz ISM band?

a)  Cerebrospinal fluid

b)  Brain

c)  Bone marrow

d)  Tongue

 

 

9.  Which body component has the lowest conductivity in the 915 MHz ISM band?

a)  Blood

b)  Brain

c)  Bone marrow

d)  Tongue

 

 

10.  What typically happens to conductivity of body tissues as frequency across the ISM bands is increased?

a)  Increases

b)  Decreases

c)  Does not change

d)  Initially increases, then decreases

 

 

Need some help? Click here for the answers and explanations.

 

 

Posted August 21, 2019           (original 8/9/2012)
RF Cascade Workbook 2018 by RF Cafe
RF Electronics Symbols for Office by RF Cafe
LadyBug Technologies LB480A RF Power Sensor Connectors - RF Cafe Res-Net Microwave - RF Cafe
About RF Cafe
Kirt Blattenberger - RF Cafe Webmaster
Copyright: 1996 - 2024
Webmaster:
    Kirt Blattenberger,
    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:  AirplanesAndRockets.com

spacer

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free