please sent me question paper of 2018 of subject science
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Name the characteristics of sound wave on which the following properties depend?
(a) Loudness
(b) Pitch
Ans.
(a) Loudness depends on amplitude
(b) Pitch depends on frequency.
Q. What is the causal organism for Swine flu? What protective measures should be taken to prevent the spread of such viral diseases?
Ans.
Virus (H1N1) is the casual organism for Swine flu.
Following are the measures that must be taken to prevent the spread of viral diseases:
Spraying pesticides.
Cleaning of garbage dumps, drains and sewers.
Q. List four main processes involved in the water cycle.
Ans.
Four main processes involved in water cycle are:
1. Evaporation: Water from oceans, lakes, rivers and other water bodies get warmed up due to sun’s heat and converted into water vapour (gas). Water vapour droplets join together to make clouds.
2. Condensation: In this step vapour gets cooled down and turns back into liquid water.
3. Precipitation: Here water (in the form of rain, snow, hail or sleet) falls from clouds in the sky.
4. Runoff: The water from clouds falls down the hills, mountains, or other inclines to join oceans, rivers, lakes, streams, etc. Most will infiltrate (soak into) the ground and will collect as underground water.
Q. What is supersaturated solution?
Ans.
Any solution containing more solute than required to prepare a saturated solution at any fixed temperature is called supersaturated solution.
Supersaturated solution is a meta-stable state i.e. it will remain in supersaturated state so long it is left undisturbed. A slight disturbance (e.g. slight rise or fall of temperature) will turn it into a saturated solution.
Q. A sheet of tin weighing 1 kg sinks in water but if the same sheet is converted into a boat, it floats. Why?
Ans.
The density of tin is higher than that of water, so the sheet of tin sinks in water. But when the same sheet of tin is converted into a boat, a lot of air is trapped in the boat causing the average density of boat to becomes lower than that of water. Therefore, it floats on water.
Q. (a) What do you mean by selectively permeable membrane? Which of the two cell wall or plasma membrane have this feature?
(b) State the functions of plasma membrane.
Answer.
(a) A selectively permeable membrane is a membrane which allows the entry and exit of some selected materials only. Since plasma membrane allows only a few or selected materials to move in and out through the cell so it is terned as selectively permeable membrane. Whereas, cell wall does not facilitate the restricted flow of materials so, it is simply permeable.
(b) Functions of plasma membrane:
It holds the various contents lying inside the cell.
It controls the movement of selected substances in and out of the cell.
It helps to maintains the shape of the cell.
It provides protection to cell from microbes and foreign substance.
Q. Find out the false statement
(a) Golgi apparatus is involved with the formation of lysosomes
(b) Nucleus, mitochondria and plastid have DNA, hence they are able to make their own structural proteins
(c) Mitochondria is said to be the power house of the cell as ATP is generated in them
(d) Cytoplasm is called as protoplasm
Ans. (d) Cytoplasm is called as protoplasm
Cytoplasm is the jelly like substance that occupies the space between the cell membrane and the nucleus. Whereas, the cytoplasm surrounded by the cell membrane and enclosing the nucleus together constitute the protoplasm.
Get the complete practice paper by clicking on the following link:
CBSE Class 9 Science Solved Practice Paper 2017-2018: Set-I
You may also like to read:
CBSE Class 9 Maths, Science, English, Hindi and Social Science Question Papers
NCERT Solutions for CBSE Class 9 Science
CBSE Class 9 Science: Chapterwise important topics and questions
(a) Loudness
(b) Pitch
Ans.
(a) Loudness depends on amplitude
(b) Pitch depends on frequency.
Q. What is the causal organism for Swine flu? What protective measures should be taken to prevent the spread of such viral diseases?
Ans.
Virus (H1N1) is the casual organism for Swine flu.
Following are the measures that must be taken to prevent the spread of viral diseases:
Spraying pesticides.
Cleaning of garbage dumps, drains and sewers.
Q. List four main processes involved in the water cycle.
Ans.
Four main processes involved in water cycle are:
1. Evaporation: Water from oceans, lakes, rivers and other water bodies get warmed up due to sun’s heat and converted into water vapour (gas). Water vapour droplets join together to make clouds.
2. Condensation: In this step vapour gets cooled down and turns back into liquid water.
3. Precipitation: Here water (in the form of rain, snow, hail or sleet) falls from clouds in the sky.
4. Runoff: The water from clouds falls down the hills, mountains, or other inclines to join oceans, rivers, lakes, streams, etc. Most will infiltrate (soak into) the ground and will collect as underground water.
Q. What is supersaturated solution?
Ans.
Any solution containing more solute than required to prepare a saturated solution at any fixed temperature is called supersaturated solution.
Supersaturated solution is a meta-stable state i.e. it will remain in supersaturated state so long it is left undisturbed. A slight disturbance (e.g. slight rise or fall of temperature) will turn it into a saturated solution.
Q. A sheet of tin weighing 1 kg sinks in water but if the same sheet is converted into a boat, it floats. Why?
Ans.
The density of tin is higher than that of water, so the sheet of tin sinks in water. But when the same sheet of tin is converted into a boat, a lot of air is trapped in the boat causing the average density of boat to becomes lower than that of water. Therefore, it floats on water.
Q. (a) What do you mean by selectively permeable membrane? Which of the two cell wall or plasma membrane have this feature?
(b) State the functions of plasma membrane.
Answer.
(a) A selectively permeable membrane is a membrane which allows the entry and exit of some selected materials only. Since plasma membrane allows only a few or selected materials to move in and out through the cell so it is terned as selectively permeable membrane. Whereas, cell wall does not facilitate the restricted flow of materials so, it is simply permeable.
(b) Functions of plasma membrane:
It holds the various contents lying inside the cell.
It controls the movement of selected substances in and out of the cell.
It helps to maintains the shape of the cell.
It provides protection to cell from microbes and foreign substance.
Q. Find out the false statement
(a) Golgi apparatus is involved with the formation of lysosomes
(b) Nucleus, mitochondria and plastid have DNA, hence they are able to make their own structural proteins
(c) Mitochondria is said to be the power house of the cell as ATP is generated in them
(d) Cytoplasm is called as protoplasm
Ans. (d) Cytoplasm is called as protoplasm
Cytoplasm is the jelly like substance that occupies the space between the cell membrane and the nucleus. Whereas, the cytoplasm surrounded by the cell membrane and enclosing the nucleus together constitute the protoplasm.
Get the complete practice paper by clicking on the following link:
CBSE Class 9 Science Solved Practice Paper 2017-2018: Set-I
You may also like to read:
CBSE Class 9 Maths, Science, English, Hindi and Social Science Question Papers
NCERT Solutions for CBSE Class 9 Science
CBSE Class 9 Science: Chapterwise important topics and questions
zoyakhan5:
please mark my answer as brainlist
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