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Prove that the kinetic energy of a freely falling object on reaching the ground is nothing but the transformation of its initial potential energy.
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If we increase the velocity of a car moving on a flat surface to four times its original speed, its potential energy ______.
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The potential energy of your body is least when you are ______.
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The following figure shows the symbols for components used in the accompanying electrical circuit. Place them at proper places and complete the circuit.
Which law can you prove with the help of above circuit?
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Resistances R1, R2, R3 and R4 are connected as shown in the figure. S1 and S2 are two keys. Discuss the current flowing in the circuit in the following cases.
- Both S1 and S2 are closed.
- Both S1 and S2 are open.
- S1 is closed but S2 is open.
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The accompanying figure shows some electrical appliances connected in a circuit in a house. Answer the following questions.
- By which method are the appliances connected?
- What must be the potential difference across individual appliances?
- Will the current passing through each appliance be the same? Justify your answer.
- Why are the domestic appliances connected in this way?
- If the T.V. stops working, will the other appliances also stop working? Explain your answer.
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Classify aqueous solutions of the following substances according to their pH into three groups: 7, more than 7, and less than 7.
Common salt, sodium acetate, hydrochloric acid, carbon dioxide, potassium bromide, calcium hydroxide, ammonium chloride, vinegar, sodium carbonate, ammonia, and sulphur dioxide.
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Explain the following cycle in your own words with a suitable diagram.
Carbon cycle.
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Which vaccines are given to infants? Why?
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How is a vaccine produced?
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How do antibiotics cure disease?
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Are the antibiotics given to humans and animals the same? Why?
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Why is it necessary to safely store the pathogens of a disease against which vaccines are to be produced?
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What are ‘broad-spectrum antibiotics'?
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Define antibiotic.
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Write note.
Industrial waste
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Write note.
Plastic waste
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Why is e-waste harmful? Express your opinion about this.
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Using a spreadsheet, draw graphs between distance and time, using the information about the movements of Amar, Akbar and Anthony given in the table below in the lesson on the Laws of Motion. What precautions will you take while drawing the graph?
| Time in the clock | Distance covered by Amar in km. |
Distance covered by Akbar in km. |
Distance covered by Anthony in km. |
| 5.00 | 0 | 0 | 0 |
| 5.30 | 20 | 18 | 14 |
| 6.00 | 40 | 36 | 28 |
| 6.30 | 60 | 42 | 42 |
| 7.00 | 80 | 70 | 56 |
| 7.30 | 100 | 95 | 70 |
| 8.00 | 120 | 120 | 84 |
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Fill in the blank to complete the statement. Justify the statement.
To draw graphs based on the quantitative information obtained in an experiment, one uses ______.
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