Section 16.1
Illumination
Practice Test
1.
In Figure 16-4, if
r
is decreased to 0.25 m, what will be the illuminance of the sphere?
a.
2224 lx
b.
556 lx
c.
139 lx
d.
8.69 lx
Hint
2.
__________ is the rate at which visible light is emitted from an object.
a.
Amplitude flux
b.
Frequency flux
c.
Luminous flux
d.
Illuminated flux
Hint
3.
A medium that allows light to pass through but does now allow the light source to be visible is__________.
a.
translucent
b.
transparent
c.
opaque
d.
transgressant
Hint
4.
Illuminance __________ as the light source moves away from the object.
a.
increases with an inverse relationship
b.
increases with an inverse square relationship
c.
decreases with an inverse square relationship
d.
decreases with an inverse relationship
Hint
5.
In Figure 16-4, if
r
is decreased to 0.25 m, what will be the total luminous flux striking the inside of the sphere?
a.
1750 lm
b.
7000 lm
c.
438 lm
d.
875 lm
Hint
6.
In Figure 16-6, if the candle were moved so that it was 2
d
to the right of the screen, but the lamp was not moved, how would the luminous intensity of the lamp have to be adjusted to make each side of the screen equally illuminated?
a.
It would need to be halved.
b.
It would need to be doubled.
c.
It would need to be quartered.
d.
It would need to be quadrupled.
Hint
7.
__________ is the rate at which light falls on a surface.
a.
Illuminance flux
b.
Luminous flux
c.
Fluorescence
d.
Illuminance
Hint
8.
A(n) __________, like the Moon, reflects light.
a.
radiating body
b.
reflecting body
c.
laminated body
d.
illuminated body
Hint
9.
A ray of light travels in a __________.
a.
straight line
b.
back-and-forth motion
c.
circle
d.
curved line
Hint
10.
Danish astronomer Ole Roemer first measured the speed of light by studying __________.
a.
the Moon
b.
how lasers travel in space
c.
the orbit of Io, a moon of Jupiter
d.
how light traveled around two mountains
Hint
11.
The two main factors affecting the illuminance of an object are __________.
a.
hardness and color
b.
distance and hardness
c.
distance and brightness
d.
color and brightness
Hint
12.
What did Roemer prove?
a.
light travels instantaneously
b.
light travels at a finite speed
c.
the correct speed of light
d.
light has no speed
Hint
13.
__________ is the speed of light defined.
a.
a
b.
c
c.
e
d.
d
Hint
14.
In Figure 16-6, if the candle were moved so that it was
d
/2 to the right of the screen, but the lamp was not moved, how would the luminous intensity of the lamp have to be adjusted to make each side of the screen equally illuminated?
a.
It would need to be quartered.
b.
It would need to be halved.
c.
It would need to be doubled.
d.
It would need to be quadrupled.
Hint
