NEW
Font size
Worksheets1.1 - Illumination Practice Exam
Total questions: 15
Worksheet time: 31mins
Light travels in a _________ path.
circular
straight
curved
In order to see an object, the object must ______.
reflect light towards your eyes
send (emit or reflect) light towards your eyes
absorb light
transmit light
We cannot change the direction of light.
True
False
What is the definition of the ray model of light?
Light travels in a straight path and its direction can be changed by encountering a boundary.
Objects that emit their own light.
The rate at which a luminous source produces light energy.
The rate at which light strikes a unit area of a surface.
Objects that can be seen due to light reflecting from them are called
Luminous flux
Luminous sources
Illumminate sources
Power sources
Objects that absorb and reflect light but do not transmit it are
transparent
translucent
opaque
luminous
All three types of objects (transparent, translucent and opaque) absorb some light.
True
False
We can see through a surface only if it
transmits light
absorbs light
reflects light
What is the definition of luminous flux?
Light travels in a straight path and its direction can be changed by encountering a boundary
Objects that emit their own light
The rate at which a luminous source produces light energy
The rate at which light strikes a unit area of a surface
The units for luminous flux, illuminance and luminous intensity, respectively, are
lumen, candela and lux
lux, candela and lumen
candela, lux and lumen
lumen, lux and candela
Luminous flux depends on the distance from the light source.
True
False
Which statement is correct?
The illuminance is directly proportional to the distance from the luminous source.
The illuminance is directly proportional to the square of the distance from the luminous source.
The illuminance is inversely proportional to the distance from the luminous source.
The lluminance is inversely proportional to the square of the distance from the luminous source.
Two lamps illuminate a screen equally from distances shown in the figure. If lamp A is rated 75 cd, what is lamp B rated?
27 cd
45 cd
130 cd
210 cd
In 1987 a supernova was observed in a neighboring galaxy. Scientists believed the galaxy was 1.66×1021 m away. How many years prior to the observation did the supernova explosion actually occur?
5.53×103 y
1.75×105 y
5.53×1012 y
1.74×1020 y
The illuminance of direct sunlight on Earth is about 1×105 lx. A light on a stage has an intensity in a certain direction of 5×106 cd. At what distance from the stage does a member of the audience experience an illuminance equal to that of sunlight?
1.4×10−1 m
7 m
10 m
5×101 m
