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Worksheetsgrade 9 light & universe revision
Total questions: 20
Worksheet time: 20mins
The distance from the center of mirror curvature and its focus equals
diameter of curvature.
quarter of the diameter of curvature.
half of the focal length.
A concave mirror of focal length 5 cm, its diameter of curvature equals ---------
5
10
15
20
A concave mirror was cut from hollow spherical glass ball of diameter 16 cm its focal length is --------
4
8
16
A spherical mirror whose radius is 60 cm, its focal length is equal to -------------
15
30
7.5
A concave mirror has a focal vertex (length) of 10 cm, the radius of curvature of its ----------------------------
10
5
20
A concave mirror with a focal length of 20 cm, and the object is placed at a of 50 cm from the mirror, the image is formed at a distance -------------------
more than 40 cm.
equals 20 cm.
more than 20 cm, and less than 40 cm.
An object when it is placed at a distance less than the focal length of the convex lens, the properties of the image formed are ---------------
real, invented and enlarged.
virtual, upright and enlarged.
real, inverted and smaller.
An object is placed at the focus of a convex lens, the image will be -------------------
between the focus and the center of curvature.
not formed
no correct answer.
If an object is put at a distance greater than the double of focal length of a convex lens the image is formed --------
at the double of focal length.
between the focus and the center of curvature
at infinity
On putting a torch in front of a convex lens at a distance equals its focal length, the light rays emerged from the lens are...
parallel
diverged.
converged.
earliest life forms began to appear on the Earth after about ----------- million years from the Big Bang.
10000
5000
12000
Planets rotate around the Sun. the Sun by the effect of the gravity of ---------
sun
moon
earth
The biggest star that can be seen clearly by people on the Earth is -------------
the Sun
Uranus
Saturn
The theory which explains how the universe originated is -------------- theory.
Big Bang
Moulton.
solar nebular
The scientist who established the nebular theory is ----------
Newton.
Chamberlain.
Laplace.
According to Laplace assumptions, the nebula gradually lost its heat, so
its size contracted only.
its revolving speed around itself increased only.
it is vanished.
Laplace theory assumed that the gaseous rings separate from nebula after its cooling and freezing forming the -----------------------
planets of the solar system
gaseous ball.
Sun
---------------- theory assumed that the solar system was originally a glowing gaseous sphere.
Fred Hoyle.
Newton.
Laplace.
theory assumed that the origin of the solar system was from the explosion of the expanded part of the Sun forming a gaseous line of a great length from the Sun due to a huge star approached to it.
Crossing star
Modern
Big Bang
The scientist(s) who established the crossing star theory is/are --------------
Newton.
Chamberlain and Moulton.
Laplace.
