SUMMATIVE ASSESSMENTS 2022-23
SUBJECT: PHYSICS
Grade : 8
Date : 23/11/2022
Max. Marks: 80
Duration : 2 hrs
Attempt all questions from Section A and any four questions from Section B. All working, including
rough work, must be clearly shown and must be done on the same sheet as the rest of the answer.
Omission of essential working will result in loss of marks. The intended marks for questions or parts
of questions are given in brackets [ ].
------------------------------------------------------------------------------------------------------------------------------------SECTION A (40 MARKS)
Attempt all questions from this section
QUESTION 1
Fill in the blanks
[10*1=10]
a) The process of conversion of solid into gas is called……………………. .
b) Molecules in matter are always in a state of……………………. .
c) A mirror that always forms an image of the same size as that of the object is a
………………………. mirror.
d) Mirrors which are used as the rear view mirror of vehicle
are……………….mirrors.
e) The ratio of speed of light in vacuum to that in a medium is called
…………………..
f) Rainbow is formed due to …………………….. of sunlight.
g) The refractive index of water is …………………… .
h) Gold leaf electroscope was developed by …………………… .
i) The process of connecting a charged object to earth is called ……………………. .
j) The SI unit of electric power is ……………………. .
QUESTION-2
Define the following
a)
b)
c)
d)
e)
Deposition
Focal length
Snell’s law
Angle of incidence
Electric power
[2*5=10]
QUESTION-3
Differentiate between the following
a)
b)
c)
d)
e)
[2*5=10]
Vaporization and condensation
Real image and virtual image
Convex mirrors and concave mirrors
Denser medium and rarer medium
Alternate current and direct current
QUESTION-4
Name the following
[1*10=10]
a) Device that automatically cuts off the current in the circuit if excess current
flows through the circuit.
b) Charging an object by bringing an uncharged object in contact with a charged
object.
c) The line passing through the centre of sphere to the exact centre of the mirror.
d) Position of the image when the object is placed at infinity.
e) The perpendicular distance between the emergent ray and the incident ray.
f) The spectrum of light that has the shortest wavelength.
g) Anything that has mass and occupies space.
h) Substances which have fixed volume but no fixed shape.
i) The process of splitting of light into its component colors.
j) Process of discarding charge.
SECTION B (40 marks)
(Answer any four from this section)
QUESTION 5
a) State the postulates of kinetic theory.
[03]
b) Draw a ray diagram to represent the image formed by a concave mirror when
the object is kept between F and C.
[03]
c) Eplain the following refraction terminologies
1) angle of incidence 2) point of incidence 3) normal 4) angle of incidence
[04]
QUESTION 6
a) Explain the 3 pin plug with live, neutral and earth wires.
b) List the uses of curved mirrors.
[03]
[03]
c) With a neat sketch explain the arrangement of molecules in solids, liquids and
gases.
[04]
QUESTION-7
a) Explain the bent effect due to refraction for a pencil dipped in a glass of
water.
[03]
b) Draw a neat, labelled diagram of a domestic electric circuit.
[03]
c) What causes lateral shift? Explain.
[04]
QUESTION-8
a) Explain the interconversion of the three states of matter.
[03]
b) Explain the following anatomy of curved mirrors.
1) principal axis 2) centre of curvature 3) radius of curvature
[03]
c) Draw a ray diagram to show the image formed by a concave mirror when the
object is placed beyond C .
[04]
QUESTION 9.
a) List any six electrical safety and precautions to be taken.
[03]
b) What do you mean by charging by induction? Explain.
[03]
c) With a neat sketch explain refraction through a glass block.
[04]
QUESTION 10
a) Explain refraction through a prism with the help of ray diagram.
[03]
b) What is dispersion of light? What causes dispersion?
[03]
c) With a neat sketch explain detection of charge using a gold leaf
electroscope.
[04]
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