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CBSE Class VIII
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Science
List of top Science Questions asked in CBSE Class VIII
In an experiment
\(4.5\)
kg of a fuel was completely burnt. The heat produced was measured to be
\(180,000\)
kJ. Calculate the calorific value of the fuel.
CBSE Class VIII
Science
Fuel Efficiency
Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
CBSE Class VIII
Science
Force of Friction
Give reasons.
Water is not used to control fires involving electrical equipment.
LPG is a better domestic fuel than wood.
Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.
CBSE Class VIII
Science
What is a Fuel?
Fill in the blanks:
Burning of wood and coal causes ___ of air.
A liquid fuel, used in homes is ___.
Fuel must be heated to its ___ ___ before it starts burning.
Fire produced by oil cannot be controlled by ___.
CBSE Class VIII
Science
What is Combustion?
The bulb does not glow in the setup shown in Fig.11.10. List the possible reasons. Explain your answer.
CBSE Class VIII
Science
Chemical Effects of Electric Current
An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?
CBSE Class VIII
Science
Contact Forces
Give two examples of each.
1. Kharif crop
2. Rabi crop
CBSE Class VIII
Science
Basic Practices of Crop Production
Write a short paragraph on the harmful effects of microorganisms.
CBSE Class VIII
Science
Harmful Microorganisms
Four children were asked to arrange forces due to rolling, static and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement.
CBSE Class VIII
Science
Increasing and Reducing Friction
Match items in column A with those in column B.
A
B
(i)
Kharif crops
(a)
Food for cattle
(ii)
Rabi crops
(b)
Urea and super phosphate
(iii)
Chemical fertilizers
(c)
Animal excreta, cow dung urine and plant waste
(iv)
Organic manure
(d)
Wheat, gram, pea
(e)
Paddy and maize
CBSE Class VIII
Science
Harvesting
The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.
CBSE Class VIII
Science
The Story of Lightning
Prepare a list of objects around you that are electroplated.
CBSE Class VIII
Science
Electroplating
Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?
CBSE Class VIII
Science
Regular and Diffused Reflection
You spill a bucket of soapy water on a marble floor accidently. Would it make it easier or more difficult for you to walk on the floor? Why
CBSE Class VIII
Science
Force of Friction
Describe characteristics and uses of coke.
CBSE Class VIII
Science
Coal
What are the major groups of microorganisms?
CBSE Class VIII
Science
Harmful Microorganisms
What are weeds? How can we control them?
CBSE Class VIII
Science
Protection from Weeds
The following Table shows the total power shortage in India from 1991–1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.
S. No.
Year
Shortage (%)
1
1991
7.9
2
1992
7.8
3
1993
8.3
4
1994
7.4
5
1995
7.1
6
1996
9.2
7
1997
11.5
CBSE Class VIII
Science
Some Natural Resources are Limited
Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?
CBSE Class VIII
Science
Earthquakes
What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?
CBSE Class VIII
Science
Role of Hormones in Initiating Reproductive Function
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
CBSE Class VIII
Science
Reflected Light Can be Reflected Again
When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?
CBSE Class VIII
Science
Chemical Effects of Electric Current
List sources of noise pollution in your surroundings.
CBSE Class VIII
Science
Noise Pollution and Control
Explain the importance of reproduction in organisms.
CBSE Class VIII
Science
Modes of Reproduction
Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30° as shown in Fig.
Draw the reflected ray from the second mirror.
CBSE Class VIII
Science
Multiple Images
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