Science Class 8th T2 2023 Solved Paper

 

Section A: Long Answer Type Questions

Q. The given figure represents a system which enables visually challenged persons to read and write.

a. What is this? Who developed it?

b. Explain how it is a great invention for visually challenged persons?

Ans:

a. This is called as Braille and it was developed by Louis braille for visually challenged persons to read and write.

b. Braille system consists of dotted letters that helps visually challenged people to read and write.

It also helps them to learn different languages.

Q.   a. State the “laws of reflection”

 b. Identify whether a regular or a diffused reflection will take place, if a beam of light strikes a ‘cardboard surface’. Justify your answer.

 Ans:

a. The laws of reflection are given as below:

1. The incident ray, reflected ray and the normal are all in the same plane.

2. The angle of incidence is equal to angle of reflection.

 

b. The cardboard has uneven surface, therefore diffused reflection will take place on it.

 

Q. The reproduction in humans is completed through various stages, Recalling those stages, differentiate between a zygote and a fetus.

 Ans:

Zygote	Fetus
It is the initial stage of development	It is the final stage of development
Zygote is stage when after fertilization	Fetus is stage when all body parts are formed
Zygote is single celled	Fetus is multicellular

 

Q. a. Define external fertilization.

     b. Explain budding in Hydra with a diagram. 

Ans:

a. External fertilization is the type of fertilization in which the fusion of the male and the female gamete takes place outside the body of female e.g., in fishes, insects, amphibians

b. In hydra, a bud forms on the body which then develop into tiny individuals. When fully mature, the bud detaches from the parent body and become Hydra.

 

 

Section B: Short Answer Type Questions

Q. Two balls are made to roll on the same time, with same force on two different surfaces. One surface is rough and another is a smooth polished one. Which of the two balls will slow down or stop first? Give reasons.

Ans: The ball that is made to roll on the rough surface will slow down first due to the friction produced by the uneven surface beneath.

 Q. Define sexual reproduction. Name some organisms that reproduce through sexual reproduction.

Ans: Sexual reproduction is a type of reproduction in which two parents are involved to form new individual.

In this type of reproduction, sperm fertilizes the egg to form zygote. E.g. mammals, birds, reptiles, higher plants.

Q. Henna made an electric setup as shown in the figure, in which the bulb does not glow. What may be the possible reasons?

Ans: The bulb may not glow due to following reasons;

a.  The liquid in the beaker may be a poor conductor of electricity.

b. The bulb might be fused.

c. The battery might be exhausted.

Q. Distinguish between Combustible and Non-combustible substances. Give examples.

Ans: Combustible substances are those substances that can easily burn in air to give heat and light. E.g., Petrol, Kerosene etc.

Non Combustible substances are those substances that do not burn in air e.g. stone, glass etc.

Section C: Very Short Answer Type Questions

Q. In a human eye, what is the function of Pupil?

Ans: Pupil  controls the amount of light entering the eye.

Q. Suggest any two ways to check pollution of Dal Lake?

Ans: Two ways to check pollution of Dal lake are given below:

a. The sewage water of Srinagar city should not be allowed to enter the Dal Lake

b. Polythene and Plastics should be banned near the Dal Lake.

c. Houseboats should not be allowed to release waste into Dal Lake

d. Regular cleaning activities should be done in the Lake. 

Q. What is meant by Conducting liquids?

Ans: The liquids that allow the electricity to pass through them are called conducting liquids e.g.; Salt water, Vinegar, Lemon juice etc.

 Q. List any two methods for purification of water.

Ans: The two methods for the purification of water are:

a. Filtration

b. Chlorination

c. Sedimentation 

Q. Say whether the two statements are ‘Correct’ or ‘Incorrect’

Statement	Correct	Incorrect
Pigeons are Oviparous	Correct
Camels are Oviparous		Incorrect
Rats are Viviparous	Correct
Butterflies are Viviparous		Incorrect

 

 Section D: Objective Type Questions

 Q. Fill in the blanks with appropriate words:

i. ________________ is a practice of removing undesirable plants from the crop fields, either manually or with the help of some tool

Ans:  Weeding

ii. Image formed in a plane mirror undergoes ______________ inversion.

Ans: Lateral

iii. While playing carom, we spread talcum powder on carom board to reduce _______________ between the board and the discs.

Ans: Friction

Q. Multiple Choice Questions

a. __________________ is commonly used chemical method for purifying water.

a. Filtration        b. Sedimentation          c. Chlorination          d. Bromination

Ans: Chlorination    

b. Murrah and Jaffarabadi are well known breeds of:

a. Hens        b. Goats     c. Buffaloes        d. Cows

Ans: Buffaloes       

c. If a beam of light is incident to a plane surface at an angle of 24⁰, the angle of reflection will be:

a. 48⁰       b. 12⁰        c. 6⁰        d. 24⁰

Ans: 24⁰

d. Taj Mahal has got discoloured due to air pollution and acid rains. The formation of acid rain can be represented as:

SO₂   + O₂   ------à   SO₃

SO₃ + H₂O ----à X

In this reaction, What is X?

a. HSO4      b. H2SO4      C. H2SO3      D. H2SO2

Ans: H2SO4

e. Splitting of light into its constituent colors is known as:

a. Multiple image formation         b. Dispersion of light

c. Lateral inversion                         d. Diffused reflection

Ans: Dispersion of Light

f. Which of the following is not a greenhouse gas?

a. Carbon dioxide         b. Sulphur dioxide       c. Nitrogen      d. Methane

Ans: Nitrogen

g. ___________ are increasingly being used for lighting, as these consume less electricity, have longer lifetime and are cheaper too.

a. LED        b. Incandescent bulbs       c. CFL     d. None of these

Ans: LED

Click here to check solved JKSCERT Science Model 2024