4 optics

Question 1

A concave mirror is used in

Answer 1

Headlights

Question 2

A chromatic aberration

Spherical aberrations

Answer 2

Can be compensated by using a compound lenses

Incidents Ray’s further from the axis of intersect slightly closer to the lens to produced distorted image

Question 3

A material with a gradually varying refractive under is said to have

Answer 3

Graded index

Graded index fibre cable - variable refractive index across its cross sectional area

Question 4

A fibre optic cable is attenuated at 29 dB/metre. This is referring to?

Attenuated pulses have their sizes and shape restored by?

Answer 4

The figure allows for when calculating power again

Regenators- ( boost signal)

Question 5

A parabolic mirror may be used to prevent

Answer 5

Spherical aberration

Question 6

Attenuation is most often caused by

Answer 6

Absorption and scattering

Question 7

Light in fibre optics is transmitted at

Answer 7

1.99 X 10 ( power of 5 ) m/s

200,000 kilometres per second

Question 8

For light to travel down a fibre optic cable , it’s angle must be

Answer 8

Same or less than the done angle

Question 9

Angle of reflection =

Answer 9

Angle of incidence

Question 10

Illumination of one lumen per metre squared is one

The unit of luminous in the SI SYSTEM is

Answer 10

Lux

Candela

Question 11

What does not require power?

What does require power in a fibre optics flight control system?

Answer 11

Passive sensor

Sensor and transmitter

Question 12

In a multi mode fibre optics system?

Answer 12

Diameter is greater than the wave length

Question 13

In refraction , SIN I/SIN R represents the

Answer 13

Refractive index

Question 14

Lasers use which source of light?

Answer 14

Coherent

Question 15

Fibre optics is used because

Optical fibres in communication

Answer 15

Greater bandwidth than electrical systems

Resistant to noise caused by stray electromagnetic signals

Question 16

Refractive index

Answer 16

Speed of light / speed of light in the medium

Question 17

Speed of light is

Miles / second =

M/s?

Km/s

Answer 17

186,000 miles/s

300,000,000 m/s

300,000 km/s

Question 18

Speed of sound

M/s?

Answer 18

343m/s

Question 19

Fibre optic receiver is a

Answer 19

Photodiode

Question 20

The numerical aperture (NA) of a fibre is a measure of

Answer 20

Max cone angle of light rays to be reflected down the fibre

Question 21

The power of a lens is measured in

Answer 21

Diopters

Question 22

Range of core diameters for optical for optical fibres are

Thickness of a single mode fibre optic ?

Answer 22

50- 100 microns

5 micro meters

Question 23

When light meets a glass / air boundary at an angle of incidence less than the critical angle?

Answer 23

Both reflection and refraction takes place

Question 24

What does a passive filter achieve?

What does an active filter achieve?

Answer 24

Sorts out/ blocks certain wavelengths

Catch certain wavelengths and converts then to other wavelengths

Question 25

Which type of electromagnetic radiation had the highest frequency?

Answer 25

Gamma

Question 26

Best light source for use with silica glass is

Answer 26

Infrared

Question 27

Regenerators are used to reduce

Answer 27

Attenuation