Saturday, August 6, 2016

Sources of energy class10 oswal solved questions

Short Answer Type Questions (2 marks each)

Q. 1. List four gases generated in a biogas plant

Ans. (i) Hydrogen (ii) Hydrogen sulphide (iii) Methane (iv) Carbon dioxide.

Q. 2. Name the major constituent of biogas. List three characteristics to prove it as an excellent fuel.

Ans. Methane is the major constituent of biogas.

Three characteristics to prove it as an excellent fuel : (i) Smokeless (ii) Leaves no residue (iii) Higher heat of combustion.

Q. 3. Mention the main use of slurry left behind in the biogas of plant. State the characteristics of the slurry on which this use is based.

Ans: Slurry is used as a manure as it is rich in nitrogen and phosphorus.

Q.4. List any four reasons why we need to look for alternate sources of energy.

Ans: Four reasons we need to look for alienate sources of energy are :

(a) Pollution due to fossil fuels. (b) Exhausting fuel reserves.(c) Increasing need. (d) Replenishment is not easy.

Q.5. List any four qualities of an ideal source of energy.

Ans: Qualifies of an Ideal Source of Energy : (a) More heat per unit mass. (b) Pollution less and smoke free (c) Cheap and Economical. (d) Easily available and easily handled. (e) Safe to transport. (any four)

Q.6. (a) What is solar cell panel ? (b) Name any two elements that are used for making solar cell panels.

Ans. (a) A combined arrangement of a large number of solar cells that can deliver sufficient electricity for practical use is known as solar cell panel. (b) Silver, Silicon.

Q. 7. Why is charcoal considered to be a better fuel than wood ?

Ans. Charcoal is better fuel than wood because (a) It is smokeless and leaves no residue. (b) It has a higher heat of combustion.

Q. 8. List any two disadvantages of using fossil fuels.

Ans. (a) Burning of coal or petroleum products lead to air pollution (b) The oxides of C, N and S are released on burning fossil fuels as acidic, oxides. It leads to acidic rain and affect water and soil.

Q.9. List two reasons which limit the usage of solar cells for harnessing energy for domestic use.

Ans. (a) Availability of the special grade silicon for making solar cells is limited. (b) The process of manufacture is expensive, silver used for interconnections of the cells in the panel further adds to the cost.

10. Biogas isconsidered to be a boon to the farmers. Give reasons.

Ans. (a) Farmers can produce clean fuel from biowastes. (b) Spent slurry is used as a best manure and can be used to generate electricity.

Q. 11. Give two advantages of using nuclear energy.

Ans. Two advantages of using nuclear energy am (a) Very small mass of Uranium yields tremendous energy. (b) The released energy can be used to produce steam and further generate electricity.

Q.12. State any three characteristics of a good source of energy. Name the gaseous fuel which has the highest calorific value.

Ans. Characteristics of Good Source of Enemy : (a) Large amount of work per unit volume/mass. (b) Easily available (c) Easy to transport. Gaseous fuel of highest calorific vlaue-hydrogen.

Q. 13. (a) Hydrogen is used as a rocket fuel. Why ? (b) List two limitations of using solar cookers.

Ans. (a) Hydrogen is comparatively a cleaner fuel than any other gaseous fuel as on its burning only water is produced which does not pollute the environment. (b) (i) Can not be used in night/cloudy days. (ii) Direction of reflector has to be changed from time to time.

Q. 14. What is a nuclear fusion reaction ? List any two advantages of nuclear fusion reactions.

Ans. Reaction in which two nuclei of lighter elements combine and form a heavy nucleus with release of tremendous amount of energy.

Two advantages : (a) Large amount of energy from a very small amount of fuel. (b) Produces non-pollutant waste/does not produce gases which pollute the environment/ muse green house effect.

Q. 15. Large scale use of nuclear energy becomes prohibitive due to some hazards. State any two major hazards associated with a nuclear power plant.

Ans. (i) Storage and disposal of spent or used fuels which decay into sub-atomic particles with harmful radiations. (ii) Nuclear waste storage and disposal result in environment contamination or accidental leakage of nuclear radiations.

Q. 16. A student constructed a model of box type solar cooker. He used a transparent plastic sheet to cover the open face of the box. He found that this cooker does not function well. What could be the possible draw backs in his model List any four draw backs.

Ans. He may not have used (a) Black painted sheet to absorb heat radiation. (b) Black cooking vessel to absorb heat radiation. (c) Glass sheet - prevents the escape of heat radiation from the box instead of plastic sheet. (d) Mirror plate reflects the sunlight to fall on the glass sheet.

For more solved questions visit
Sources of energy solved question for board exam by jsuniltutorial

Friday, August 5, 2016

8th Class Cell structure and function solved questions(Biology)

Q  Name the cells having branches structure.

Ans Nerve Cell.

Q Why cells could not be observed before seventeenth century?

Ans Cells could not be observed before seventeenth century because till that time microscope was not invented.

Q Why plant cell have cell wall?

Ans Plant cells need protection against variations in temperature, high wind speed, atmospheric moisture, etc.
They are exposed to these variations because they cannot move. That's why they have cell wall.

Q Which organism has the smallest cell?

Ans  Mycoplasmas, a bacteria has the smallest cell of the size of 0.1 micron i.e. ten thousandth part of a mill metre. '

Q  Which is the largest cell visible by unaided eye?

Ans Ostrich egg has the largest visible cell by unaided eye.

Q Name the four elements, which fonn major part of protoplasm.

Ans These are carbon, hydrogen, oxygen and nitrogen.

Q Give two examples of prokaryotes.

Ans Bacteria and blue green algae.

Q  Name the largest organelle present in a cell.

Ans Vacuoles

Q Why do we stain the small components of section, before seeing under the microscope? Name a
stain. Marks (2)

Ans) Staining with coloured dyes makes the parts clearly visible. The dyes react with cellular components to give  colour to the components. Eosin is a stain which gives a red orange colour.

Q Why is the cell called basic unit of living organism?

Ans Cell is the structural and functional unit of an organism because a cell in itself is the smallest part of an  organism which is capable of functioning independently and can carry out the fundamental duties of life like reproduction, metabolism (photosynthesis and/or respiration).

Q What is the function of cell membrane?
Ans The function of the cell membrane is to let particles move in and out, to or from the cell.

Q Why mitochondria is called powerhouse of cell?

Ans Mitochondria provide the energy to the cell for carrying out various activities. So it is called powerhouse of cell.

Q. Write the functions of the following a) Mitochondria b) Chromosomes c) Plastids Marks (3)

Ans Functions are as follows:

( a ) Mitochondria provide the energy to the cell for carrying out various activities. Mitochondria are rod shaped and very minute bodies present in cytoplasm. They are concerned with release of energy from food during respiration. Because of this they are often referred to as the power house of the cell.

(b) Chromosomes transfer the characters from parents to the next generation.

(c) Plastids found in plant only and are the largest cell organelle containing pigments. They give colour to flowers and fruits, which help in pollination. 
The green plastids in the plants are celled chloroplasts. They help in the synthesis of food.
The red colour plastid in tomato is due to the plastids with red pigments  

Q.How does nucleus help in transmission of characters from parents to children?

Ans Nucleus contains chromosomes, which have genes present on them. These genes carry information about characters of an individual. These genes are transferred from parent to children and hence characters are transmitted from parents to children.

Full E-Notes for CBSE & NCERT class 8th given below for download     Download File
For more related material - 8th BIOLOGY

Tuesday, December 8, 2015

class9 why do we fall ill solved questions


1. Define health.

Ans. Health is defined as the state of complete physical, mental and social well being.

2. What is disease?
Ans. Disease is a departure from normal health through structural or functional disorder of the body.

3. What is the most important factor that keeps us healthy?

Ans. Our social environment is an important factor in our individual health.

4. List any two conditions essential for good health.

Ans. Conditions essential for good health are:

i. to have a balanced diet and varied diet.

ii. avoid wrong habits like drinking alcohol and drug consumption.

5. List any two conditions essential for being free of disease.

Ans. Conditions essential for being free of disease are:

i. maintain personal hygeine.

ii. keep environment clean and hygiene.

6. Give examples of diseases which are caused by intrinsic sources and extrinsic sources.

Ans. Diseases caused by intrinsic sources:  Heart attack, Kidney failure, Sickle cell anaemia, Diabetes, etc.

Diseases caused by extrinsic sources:  Night blindness, Malaria, Rabies, Hepatitis, Dysentery, etc.

7. Why is public cleanliness important for individual health?

Ans. Many public places are left messy and unsightly. Some industries pollute the environment. In many  drains water flows uncovered or water is stagnant. All these enhance the growth of germs and chances  of infection. Therefore, public cleanliness is important for individual health.

8. Give at least two examples of each:i. Physical diseases       ii. Mental disease     iii. Deficiency diseases

Ans. i. Cold and bone fracture     ii. Depression ,Schizophrenia     iii. Night blindness and Scurvy

9. Enlist some intrinsic and extrinsic factors which affect human health.

Ans. Intrinsic factors:
i. Malfunctioning of some vital body organs and immune systems
ii. Genetic disorder        
iii. Hormonal imbalance
Extrinsic factors:
i. Unbalanced or inadequate diet
ii. Disease causing organisms
iii. Pollutants
iv. Bad food and drinking habits

10.What do you mean by symptoms of diseases?

Ans. Symptoms of disease are the things we feel as being ‘wrong’. Symptoms are the physical or behavioral signs of a suspected injury or disease.

11.Define communicable diseases.

Ans. Communicable disease is defined as the disease that is transmitted through direct contact with 
an  infected individual or indirectly through a vector.

12.Differentiate between acute and chronic diseases.


Acute Diseases
Chronic Diseases
Last for short duration.
Last for long duration
Damage to body
Cause less damage to
Cause great damage to

body tissues and parts
body tissues and parts
Common cold

13.Give one word for:

i. Diseases which can spread from one person to another 

ii. Diseases which are present since birth

iii. Diseases which last for short duration

iv. Disease which last for longer duration

Ans. i. Infectious diseases or communicable diseases               ii. Congenital diseases

iii. Acute diseases                                                                      iv. Chronic diseases

14.Give examples of:
i. Infectious diseases     ii. Non-infectious diseases    iii. Acute diseases    iv. Chronic diseases

Ans. i. Malaria              ii. Heart-attack                       iii. Common cold     iv. Tuberculosis

15.What do you understand by non-communicable diseases?

Ans. A non-communicable disease a disease which do not spread through direct contact with an
infected individual or indirectly through vector. Such diseases may result from genetic or lifestyle 

16.What are the causes of non-infectious diseases?

Ans. Following are the causes of non-infectious diseases:
i. deficiency of certain essential substances in our diet
ii. degeneration and wearing out of tissues
iii. uncontrolled proliferation of tissues in any part of body
iv. defects in metabolic pathways
v. damage and injuries of tissues and body parts by accidents

17.What are congenital disorders? How do they occur? Can they be cured?

Ans. Congenital disease is a disease or disorder that is inherited genetically and present at the time of
These diseases are caused because of genetic abnormalities, metabolic disorders or malfunctioning of
any organ in body.
No, congenital diseases cannot be cured. They are permanent.

18.Which antiviral protein is secreted by our body in case of viral infection?

Ans. Interferon is secreted by our body in case of viral infection.

19.Name the bacteria that are responsible for peptic ulcers.

Ans. Helicobacter pylori is responsible for peptic ulcers.

20.Why does a man suffering from an acute disease suffer less than a man suffering from a chronic disease?

Ans. Chronic diseases last a long time and hence, they damage body parts and tissues to a greater extent than an acute disease, which lasts for a very short duration. Therefore, a patient suffering from a chronic disease endures more agony than a patient suffering from an acute disease.

21.Define vector.

Ans. Vector is defined as an agent (person or animal or microorganism) that carries and transmit a disease.

22.Which viral disease suppresses bodies immune system?


23.What is vaccination?

Ans. The process of injecting killed or attenuated microbes in order to activate the immune system against disease causing microbes to prevent from disease/s is vaccination.

24.Name the causative agent of sleeping sickness.

Ans. Sleeping sickness is caused by Trypanosoma.

25.Give at least one example of each:

i. disease caused by bacteria                    ii. disease caused by virus

iii. disease caused by protozoa               iv. disease spread through vector

Ans. i. Tuberculosis ii. Jaundice iii. Sleeping sickness iv. Malaria

26. Name the organs which are mainly affected by the following diseases:
i. Jaundice               ii. Hepatitis                   iii. AIDS                     iv. Encephalitis

Ans. i. Liver ii. Liver iii. Immune system iv. Brain

27.What preventive measures can be taken against infectious diseases?

Ans. Diseases can be prevented in general and specific ways.

a. General ways of prevention are:

I. Community hygiene is one of the basic methods to the prevention of infectious diseases

II. Air-borne diseases can be controlled by making living conditions that are not overcrowded.

III. Water-borne diseases can be prevented by providing safe drinking water.

IV. Vector-borne infections can be checked by making vector free environment

V. Specific way of preventing infectious diseases is to immunize surrounding individuals against infectious diseases (if possible).

28.Write the causative agents for the following diseases:

i. Tuberculosis               ii. Jaundice                  iii. Malaria             iv. Polio

Ans. i. Mycobacterium tuberculosis ii. Hepatitis B virus iii. Plasmodium sp. iv. Polio virus

29.What are the different modes of transmission of diseases? Also give examples of diseases of each mode of transmission.

Ans. Infectious diseases can be spread through the following agents:

1) Through air: Cough or sneeze of an infected person may cause infection to a healthy person if he inhales the droplets containing microbes. Diseases like common-cold, tuberculosis, pneumonia, etc.,  are  spread through air.

2) Through water: Consumption of water contaminated with the spores of bacteria or disease causing microbes can cause disease like cholera, amoebiasis.

3) Through sexual contact: Unsafe sexual contact with an infected partner many lead to may sexually transmitted diseases. For example, syphilis, AIDS, genital warts, etc.

4) Through vectors: Vectors (animals or microorganisms) carry the infecting agents from a sick person to another potential host. They act as a carrier of a disease or infection. Malaria is a very good example of this type of transmission of diseases.

30.How do antibiotics work against bacteria?

Ans. Antibiotics are drugs used to treat infections caused by bacteria. Some antibiotics, such as the penicillins, are 'bactericidal'. They work by killing bacteria. They do this by interfering with the 
formation  of the cell walls or cell contents of the bacteria. As a result bacteria die. Other antibiotics are  'bacteriostatic'. They work by stopping bacteria multiplying. Excess use of antibiotics can lead to 
bacteria  becoming resistant to them so it's important to only take them when necessary.

Class IX Biology Chapter Chapter: Why do we fall ill? NCERT Solutions 
Biology Science Ch-13. Why do we fall ill 
CCE Test Paper Biology Chapter: Why do we fall ill? Solved Questions 
NCERT Solved Board Questions for Class 9th Science: Ch-13. Why do we fall ill? 
Class IX Biology Ch-13.Why do we fall ill-Chapter Notes 

Monday, September 14, 2015

2015-2016 Latest 10th original School CBSE paper Science SA- 1 (Sep-2015)

Original Question Paper of Science[Exam 2015] Conducted in different CBSE schoolsSA-1 Class 9th & 10th Latest Papers (September 2015)

10th Science SA- 1 (2015) original paper_new -1
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10th Social Science sa-1 original paper 2015-16-1
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10th SA-1 CBSE Original Maths Paper 2015-2016 -1
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SA-1 class 9 Latest Original CBSE Question for Maths 2015

Exam conducted in different CBSE schools

SA-1 class 9 Maths Original Paper 2015-2016-1
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SA-1 class 9 Science Original Paper 2015-2016-1
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Label: IX Sample paper SA-1, X Sample Papers SA-1,
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