- Those objects which emit
light are called luminous
objects. Example Sun, bulb, candle.
- Those objects which do
not emit light or only be seen when light is reflected
from them is called Non luminous
object. Example moon, earth.
- On
the base of optical properties, Objects are classified into opaque, transparent
and translucent.
- Opaque: If you cannot
see through an object then the object is
opaque because opaque materials do not allow light to pass through them.
- Translucent: We cannot
clearly see through the object then the object is translucent
objects. Example wax paper, tissue etc.
- Transparent
object: The object through which we can see clearly. Example: air, glass, water.
- Light travels in a straight line. When its path is blocked by an opaque object then a shadow is formed.
- Pinhole camera works on the principle that light travels in a straight line.
- The Sun
is the largest natural source of light.
- Moon is non-luminous
object.
- Sun is luminous object.
The ……. is the
largest natural source of light?
a) Moon
b) Star
c) Sun
d) Satellite
c
The speed of light in vacuum is…..
NTS Past ----CT Test
a) 300,000 km/s
b) 400,000 km/s
c) 500,000 km/s
d) 600,000 km/s
a
Fastest thing in universe is;
a) Light
b) Sound
c) Heat
d) All of these
a
Such objects, which emit light, are called …… objects.
a) Bright
b) Luminous
c) Non-luminous
d) Transparent
b
The objects that do not give out light of their own are called;
a) Luminous objects
b) Non- Luminous objects
c) Dark objects
d) Translucent object
b
