Saturday, 3 March 2012

CBSE Class 7th (VII) English | Chapter 8. Fire: Friend and Foe-Solved Exercises

Intext Questions (Comprehension Check (Page 118))

Question 1.Mark the correct answer in each of the following.

  • Early man was frightened of
    1. lightning and volcanoes.
    2. the damage caused by them.
    3. fire.

    1. Fire is energy.
    2. Fire is heat and light.
    3. Fire is the result of a chemical reaction.
    Answer:
    1. Early man was frightened of -(c) fire.
    2. (c) Fire is the result of a chemical reaction.
    Question 2. From the boxes given below choose the one with correct order of the following sentences.
    1. That is fire.
    2. A chemical reaction take place.
    3. Energy in the form of heat and light is released.
    4. Oxygen combines with carbon and hydrogen.
    (i) (ii) (iii) (iv)  (ii) (iii) (i) (iv)
    (iv) (iii) (ii) (i)  (iv) (ii) (iii) (i)
    Answer: The correct order is : (iv) (ii) (iii) (i)
    1. Oxygen combines with carbon and hydrogen.
    2. A chemical reaction take place.
    3. Energy in the form of heat and light is released.
    4. That is fire.
    ------------------------------------------------------

    Textbook Questions (Working with the Text)

    Answer the following Questions
    Question 1. What do you understand by the 'flash point' of a fuel? Answer: Every fuel like paper, coal or wood begins to burn only at a particular temperature. This temperature is provided generally with a lighted match. This temperature is called the flash point of kindling temperature of the fuel.
    Question 2.
    1. What are some common used of fire?
    2. In what sense is it a 'bad master"?
    Answer:
    1. The common uses of fire are to cook food in the kitchen, warm our homes in winter. Beside many industrial process make use of fire for various type of activities in production of goods and services. In thermal plants fire from coal is used to generate electricity
    2. If fire gets out of control, it can be dangerous. It burns homes, shops and vast areas of forests. It also kills and injures hundreds of people every year.
    Question 3. Match the items in Column A with those in Column B:
    AB

    1. fuel
    2. oxygen
    3. heat

    - lighted matchstick
    -air
    -coal
    -burning coal
    -wood
    -smouldering paper
    -cooking gas
    Answer:
    AB
    1. fuel
    2. oxygen
    3. heat

    1. coal, wood, cooking gas
    2. air
    3. lighted match stick, burning coal, smouldering paper
    Question 4. What are the three main ways in which a fire can be controlled or put out? Answer: The three main ways in which a fire can be controlled or put out are :
    1. By Preventing oxygen from reaching it. No supply of oxygen means no fire. This can be done by throwing a damp blanket or spraying foam of dry carbon dioxide.
    2. By Removing the inflammable material near the fire like Gas, Oil, wood, Plastic etc
    3. By lowering the temperature below Flash Point of the burning material, using water etc
     
  • Question 5. Match the items in Box A with those in box B.
    A

    1. To burn paper or a piece of wood
    2. Small fire can be put out
    3. When water is spread on fire.
    4. A carbon dioxide extinguisher is the best thing
    5. Space left between buildings.
    B

    • it absorb the heat from the burning material and lowers the temperature
    • reduces the risk of fire.
    • with a damp blanket.
    • we heat it before it catches fire.
    • to put out an electrical fire.
    Answer:
    A

    1. To burn paper or a piece of wood -- we heat it before it catches fire.
    2. Small fire can be put out -- with a damp blanket.
    3. When water is spread on fire. -- it absorb the heat from the burning material and lowers the temperature
    4. A carbon dioxide extinguisher is the best thing -- to put out an electrical fire.
    5. Space left between buildings. -- reduces the risk of fire.

    Question 6. Why does a burning candle go out when you blow on it?
    Answer: When we blow on burning candle, we remove the hot air around the flame. Thus, we bring down its temperature below the flash point. Then the candle goes out.

    Question 7. Spraying water is not a good way of putting out an oil fire or an electrical fire? Why not?
    Answer: Oil fire cannot be put out by spraying water on it. The reason is that the oil floats to the top of water and continues to burn. Secondly, it can flow quickly carrying the burning oil. Thus the fire spreads. Water should not be used on electrical fire. Water is a good conductor of electricity. So the person spraying water can get electric shock and be killed.
    Question 8. What are some of the things you should do to prevent a fire at home and in the school?
    Answer:
    1. Keep the gas cylinder at a safe distance. Check the tube from time to time. The foul smell of the leaking gas should be tackled at the earliest.
    2. The school and office buildings often catch fire because of electric short circuit. So we should avoid overload and replace old wires. The electric fuses and MCBs should also be checked from time to time.
    3. We must not keep inflammable or combustible things like kerosene and petrol in our homes.
    4. Fire extinguishers be installed in high-rise buildings.
    ------------------------------------------------------------

    Working with Language

    1. Read the following sentences. To burn paper or a piece of wood, we heat it before it catches fire. We generally do it with alighted match. Every fuel has a particular temperature at which it burns. The verbs in italics are in the simple present tense. when we use it, we are not thinking only about the present . We use it to say that something happens all the time or repeatedly, or that something in true is general. Find ten examples of verbs in the simple present tense in the text 'Fire: Friend and Foe' and write them down here. Do not include any passive verbs.
    ___________________________
    ___________________________
    ___________________________

  • Answer: Students do themselves.
    Question 2. Fill in the blanks in the sentences below with words in the box. you may use a word more than once.
    carbon, cause, fire, smother
    1. Gandhiji's life was devoted to the ______ of justice and fair play.
    2. Have you insured your house against ______?
    3. Diamond is nothing but ______ in its pure from.
    4. If you put to much coal on the fire at once you will ______ it.
    5. Smoking is said to be the main ______ of heart disease.
    6. When asked by an ambitious writer whether he should put some ______ into his stories, Somerset Maugham murmured, "No, the other way round".
    7. She is a ______ copy of her mother.
    8. It is often difficult to ______ a yawn when you listen to as long speech on the value of time.
    Answer:
    carbon, cause, fire, smother
    1. Gandhiji's life was devoted to the cause of justice and fair play.
    2. Have you insured your house against fire?
    3. Diamond is nothing but carbon in its pure from.
    4. If you put to much coal on the fire at once you will smother it.
    5. Smoking is said to be the main cause of heart disease.
    6. When asked by an ambitious writer whether he should put some fire into his stories, Somerset Maugham murmured, "No, the other way round".
    7. She is a carbon copy of her mother.
    8. It is often difficult to smother a yawn when you listen to as long speech on the value of time.
    Question 3. One words is italicised in each sentence. Find its opposite in the box and fill in the blanks.
    spending, shut, destroy, subtract, increase
    1. You were required to keep all the doors open, not ______.
    2. Pupil : What mark did I get in yesterday's Maths test?
      Teacher : You got what you get when you add five and five and _____ ten from the total.
    3. Run four Kilometers a day to preserve your health. Run a lot to ______ it.
    4. If a doctor advises a lean and lanky patient to reduce his weight further, be sure he is doing it to ______ his income.
    5. The world is too much with us; late and soon, Getting and ______ we lay waste our powers.
      --Wordsworth
    Answer:
    spending, shut, destroy, subtract, increase
    1. You were required to keep all the doors open, not shut.
    2. Pupil : What mark did I get in yesterday's Maths test?
      Teacher : You got what you get when you add five and five and subtract ten from the total.
    3. Run four Kilometres a day to preserve your health Run a lot to destroy it.
    4. If a doctor advises a lean and lanky patient to reduce his weight further, be sure he is doing it to increase his income.
    5. The world is too much with us; late and soon. Getting and spending we lay waste our powers.
      --Wordsworth
    Question 4. Use the words given in the box to fill in the blanks in the sentences below.
    across, along, past, through
    1. The cat chased the mouse ______ the lawn.
    2. We were not allowed to cross the frontier. So we drove _____ it as far we could an came back happy.
    3. The horse went ____ the winning post and had to be stopped with difficulty.
    4. It is not difficult to see ______ your plan. Any one can see your motive.
    5. Go ______ the yellow line, then turn left. You will reach the post office in five minutes.
    Answer:
    across, along, past, through
    1. The cat chased the mouse across the lawn.
    2. We were not allowed to cross the frontier. So we drove along it as far we could an came back happy.
    3. The horse went past the winning post and had to be stopped with difficulty.
    4. It is not difficult to see through your plan. Any one can see your motive.
    5. Go along the yellow line, then turn left. You will reach the post office in five minutes.

2 comments:

  1. Replies
    1. thank for solutions of all questions. it is very nice to study. it is help to study.
      by tripti meena

      Delete