chapter 10

Question 1

A forward biased diode that releases light energy is called a(n) ? .

Answer 1

light-emitting diode (LED)

Question 2

An optoelectronic device that emits light of one frequency or color is called a(n) ? .

Answer 2

laser diode

Question 3

What is the proper name for a diode that emits infrared light when forward biased?

Answer 3

IRED

Question 4

The forward voltage drop of light-emitting diodes and infrared-emitting diodes is the same as the forward voltage drop for silicon diodes.

Answer 4

false

The forward voltage drop of light-emitting diodes and infrared-emitting diodes is greater than the forward voltage drop for silicon diodes.

Question 5

A seven-segment display is an arrangement of seven light emitting diodes used to display numbers 0 through 9.

Answer 5

true

Question 6

What type of diode is sensitive to light and exhibits less internal bias in the reverse bias mode when exposed to a light source?

Answer 6

photodiode

Question 7

A(n) ? is a device that is made up of two separate devices—an LED and a light-sensing diode, or photodiode.

Answer 7

optocoupler

Question 8

What size resistor will be required to connect an LED with 1.8-volt forward drop to a 24-volt DC power supply? (Assume 20-milliamp current.)

Answer 8

1110 ohms

Question 9

What would be the recommended wattage value for the resistor in the previous question? (Use a safety factor of 2 and round the answer up to the nearest quarter watt.)

Answer 9

1 w

Question 10

Photodiodes in photoconductive mode are normally operated in forward bias.

Answer 10

false

Question 11

A phototransistor is more sensitive to light than a photodarlington.

Answer 11

false

Question 12

Which light sensitive device could be used to switch AC current?

Answer 12

Phototriac

Question 13

The primary function of a(n) ? is to provide electrical separation between input and output signals.

Answer 13

optoisolator

Question 14

Which of the following is not an advantage of fiber optic cable over conventional copper cable?

Answer 14

Smaller data capacity for long runs

Question 15

An optoelectronic device that emits monochromatic light is called a ? .

Answer 15

laser diode

Question 16

The principle of operation of fiber optic cable is total internal reflection of light.

Answer 16

true

Question 17

Light strikes a transparent surface and divides into a reflected beam and a refracted, or bent, beam.

Answer 17

true

Question 18

When light strikes a transparent surface at less than the critical angle, the light is reflected.

Answer 18

false

Question 19

Which of the following is a configuration for fiber optic cable that is associated with the path the light takes through the cable?

Answer 19

Graded-index multimode fiber Incorrect

Single-mode fiber Incorrect

Step-index multimode fiber

Question 20

Which type of fiber is best suited for long distance high speed data applications?

Answer 20

Single-mode fiber

Question 21

Fiber optic cables used for data transmission typically carry light signals at levels ? or less.

Answer 21

100 µW

Question 22

Which of the following parts are used to make up a fiber optic cable?

Answer 22

Buffer jacket

Cladding

Core

Outer jacket or protective sheath

Silicon coating

Strength member