InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Compare and contrast bio-mass and hydro-electricity as sources of energy. |
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Answer» (i) Bio-mass is a renewable source of energy only if we plant trees in a planned manner which is not the case with hydroelectricity. (ii) The energy from bio-mass can be obtained by using a chullah or a gobar gas plant whereas hydroelectricity requires construction of dams on rivers. (iii) Bio-mass provides pollution-free enegry only when converted into biogas whereas hyroelectricity is totally pollution-free. |
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| 2. |
Which of the following is not an example of bio-mass energy source ? (a) wood (b) gobar gas ( c) atomic energy (d) coal.A. woodB. gobar gasC. nuclear energyD. coal |
| Answer» Correct Answer - A::C | |
| 3. |
Bituminous coal is the finest quality of coal. |
| Answer» Correct Answer - F | |
| 4. |
What are many thermal power plants set up near coal or oil fields ? |
| Answer» Coal or petroleum is used to heat water to generate steam required for running the turbines in thermal power plants. Thus, if thermal power plants are set up near coal or oil fields, the cost of transportation of coal or petroleum is greatly reduced. | |
| 5. |
Solar cells are made of :A. conductorsB. insulatorsC. semi-conductorsD. super-conductors |
| Answer» Correct Answer - C | |
| 6. |
The value of solar constant is :A. 1.4 kWhB. 1.4 kW/mC. `1.4 kW//m^(2)`D. `1.4 kW//m^(3)` |
| Answer» Correct Answer - C | |
| 7. |
The radiations present in sunlight which make a solar cooker work are :A. visible light raysB. ultraviolet raysC. cosmic raysD. infrared rays |
| Answer» Correct Answer - D | |
| 8. |
Explain what is meant by anaerobic degradation ? |
| Answer» Anaerobic degradation is the process of decomposition of animal and plant wastes by anaerobic bacteria in the presence of water but in the absence of air to form methane (the main constituent of biogas), carbon dioxide, hydrogen and hydrogen sulphide. Anaerobic bacteria (or anaerobe) is a minute organism that can live without free oxygen. | |
| 9. |
Name two appliances that use solar energy directly. |
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Answer» (i) Solar cooker (ii) Solar water heater. |
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| 10. |
Why is there a need to harness non-conventional sources of energy ? Give two main reasons. |
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Answer» (i) The energy demands are increasing rapidly due to : (a) population explosion (b) our efforts in improve the quality of life by adopting faster means of transport and travel, rapid industrialisation and extensive use of energy-fed home appliances. (ii) Fossil fuels (coal, petroleum, `LPG`, Natural gas) are fast depleting. |
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| 11. |
The mass numbers of four different elements A, B, C and D are 2, 35, 135 and 239 respectively. Which of them would provide the most suitable fuel for (i) nuclear fission, and (ii) nuclear fusion? |
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Answer» (i) In the process of nuclear fussion, a very big atom (having a very big mass number) is used as a fuel. Here, out of the four elements A, B, C and D, the atom of element D is the biggest, having a mass number of 239. So, element D would provide the most suitable fuel for nuclear fission. (ii) In the process of nuclear fusion, a very small atom (having a very small mass number) is used as a fuel. Here, out of the four elements A, B, C and D, the atom of element A is the smallest, having a mass number of 2. So, element A would provide the most suitable fuel for nuclear fusion. Before we go further and discuss the consequences of using energy sources on the environment. |
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| 12. |
A solar water heater cannot be used to get hot water on :A. a sunny dayB. a cloudy dayC. a hot dayD. a windy day |
| Answer» Correct Answer - B | |
| 13. |
What are the two main categories of sources energy ? |
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Answer» (i) Renewable sources of energy (ii) Non-renewable sources of energy. |
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| 14. |
Why are we looking at alternative sources of energy ? |
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Answer» We are looking at alternative sources of energy mainly due to two reasons : (i) because the fossil fuels and nuclear fuels present in the earth are limited which may not last for long, and (ii) because of the undesirable effects of pollution both from the burning of fossil fuels and from the radioactive wastes of the nuclear power plants. |
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| 15. |
The calories we burn during exercise come from three different sources : carbohydrates, fat and proteins. The type of fuel our body uses during a workout depends on the nature of the activity performed. (i) Which of the above mentioned fuel/fuels is (are) used in moderate cycling (10 miles/hour) workout ? (ii) When is the cycling workout categorised as vigorous ? Which fuel does it burn then ? (iii) Which is the least preferred source of energy during exercise ? (iv) What is importance of exercise in our life ? |
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Answer» (i) Both fat and carbohydrates (roughly `60 %` of the energy comes out from fat) (ii) When cycling speed exceeds `10 miles//hour`, the workout is categorised as vigorous. At this level, the primary fuel shifts from fat to stored carbohydrates. (iii) Protein is the least preferred source of energy during exercise. When glycogen stores (from carbohydrates) are low or depleted, as much as `10 %` of the fuel for exercise comes from proteins. (iv) Lack of exercise results in obesity which is the mother of all diseases - hypertension, diabetes, heart diseases-to mention just a few. |
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| 16. |
A newly planted sapling usually grows and matures into a tree in more than :A. 50 yearsB. 25 yearsC. 45 yearsD. 15 years |
| Answer» Correct Answer - D | |
| 17. |
The fuel having the lowest calorific value is :A. coalB. woodC. charcoalD. kerosene |
| Answer» Correct Answer - B | |
| 18. |
The fuel having a calorific value of 55 kJ/g is likely to be :A. biogasB. methane gasC. hydrogen gas D. natural gas |
| Answer» Correct Answer - B | |
| 19. |
What are the advantages of coke over coal ? |
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Answer» (i) Coke produces more heat than an equal mass of coal. (ii) It produces ni smoke on burning and leaves no residue and as such does not cause air pollution. (iii) It is used as a reducing agent in the extraction of metals from their ores. |
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| 20. |
The unit of calorific value is `Jg^(-1) .^(@)C^(-1)`. |
| Answer» Correct Answer - F | |
| 21. |
Which of the following fuels has the highest calorific value ?A. natural gasB. methane gasC. hydrogen gasD. biogas |
| Answer» Correct Answer - C | |
| 22. |
Name the product obtained by the fractional disatillation of crude oil which is used is used as a furnace fuel. |
| Answer» Correct Answer - Fuel oil. | |
| 23. |
What is slurry ? |
| Answer» Semifluid mixture of animal dung(and other waste materials) and water in equal amounts. | |
| 24. |
(a) Which is a better fuel : coke or coal ? (b) Which fuel has the largest calorific value ? |
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Answer» (a) Coke, as it does not produce smoke on burning. (b) Hydrogen `(150 kJ//g)`. |
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| 25. |
Name a fraction obtained during refining of petroleum which does not find use as a fuel. |
| Answer» Lubricating oil. | |
| 26. |
(a) What is the origin of the word petroleum ? (b) Which petroleum products are not fuels ? |
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Answer» (a) Petra stands for rock and oleum for oil. (b) Asphalt, Lubricating oil, Paraffin wax. |
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| 27. |
The minimum speed of wind necessary for the satisfactory working of a wind generator to produce electricity is about :A. 15 km/hB. 25 km/hC. 35 km/hD. 45 km/h |
| Answer» Correct Answer - A | |
| 28. |
Choose the incorrect statement regarding wind power.A. It is expected to harness wind power to maximum in open space.B. The potential energy content of wind blowing at high attitudes is the source of wind power.C. Wind hitting at the blades of a windmill causes them to rotate. The rotation thus achieved can be utilised furtherD. One possible method of utilising the energy of rotational motion on the blades of a windmill is to run to turbine of an electric generator. |
| Answer» Correct Answer - B | |
| 29. |
Statement-1 : Combustion or burning takes place only in the presence of oxygen. Statement-2: Oxygen is supporter for combustion.A. statement (1) and (2) are trueB. Statement (1) is true and statement (2) is falseC. Statement (1) and (2) are falseD. Statement (1) is false and statement (2) is true. |
| Answer» Correct Answer - D | |
| 30. |
The main constituent of petroleum gas isA. ethaneB. propaneC. methaneD. All the above |
| Answer» Correct Answer - C | |
| 31. |
When the coils of an electric generator rotate in a megnatic field,A. the mechanical energy change into electric energy.B. the thermal energy changes into electric energy.C. the solar energy changes into electric energyD. the wind energy changes into electric energy. |
| Answer» Correct Answer - A | |
| 32. |
A wind energy farm converts _______.A. solar energy to wind energyB. wind energy to wind energyC. electrical energy to wind energyD. wind energy to solar energy |
| Answer» Correct Answer - B | |
| 33. |
Match the entries given in column A with appropriate ones in column B |
| Answer» Correct Answer - A:d B:f C:j D:a E:g F:I G: b H :c I:e J:h | |
| 34. |
The energy possessed by steam produced by geothermal energy is _________A. potential energyB. kinetic energyC. hydroelectric energyD. Both (a) and (b) |
| Answer» Correct Answer - D | |
| 35. |
Geothermal energy is produced by the :A. fission of radioactive materialsB. burning of coal inside the coal minesC. combustion of natural gas deep inside the earthD. fusion of radioactive substances |
| Answer» Correct Answer - A | |
| 36. |
Why are solar heating devices painted black form inside ? |
| Answer» Black surfaces absorb the maximum amount of heat from the solar radiation. | |
| 37. |
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel `CNG` ? Why or why not ? |
| Answer» Hydrogen is a cleaner fuel than `CNG`. This is due to the reason that it produces water on burning whereas `CNG` on burning produces `CO_2`, though much less than that produced when coal or oil is burnt. A spaceship carries oxygen (in liquid form) along with it to burn hydrogen (in liquid form) as a fuel. | |
| 38. |
What steps would you suggest to minimise environmental pollution caused by burning of fossil fuels ? |
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Answer» The following steps can be would suggested to minimise environmental pollution caused by burning of fossil fuels (i) Using smokless appliances and using various techniques to reduce the escape of harmful gases. (ii) Converting land into forest by planting trees. (iii) Using clean fuels like CNG, LPG, etc. (iv) By using public transport instead of private vehicles. (v) By increasing the efficiency of combustion process. |
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| 39. |
How is the increased demant for energy affecting our environment adversely ? |
| Answer» We use fossil fuels to meet the increased energy demands. As a result of this, pollution so produces adversely change the composition of the environment. | |
| 40. |
What is our biggest source of energy ? |
| Answer» The Sun is the biggest source for all our energy requirements. It produces energy due to to nculear fusion. | |
| 41. |
How is hydroelectric power generated ? |
| Answer» The kinetic energy of water flowing out of the gates of a dam is converted into electric enegry. | |
| 42. |
What are the advantages of unclear energy? |
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Answer» The advantages of nuclear energy are: `rarr` Large amount of energy is produced per unit mass. `rarr` It does not produce smoke. It is a clean energy. `rarr` Fission of one atom of uranium produces 10 million times the energy released by burning of one atom of carbon. `rarr` Fusion of four hydrogen atoms produces huge amount of energy approximately equal to 27 MeV. |
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| 43. |
What are the avantages of nuclear energy ? |
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Answer» (1) To produce a certain amount of energy, the mass of nuclear fuel `(U-235)` required is extremely small. (2) In a nuclear power plant, the nuclear fuel supplies energy over a long span of time. |
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| 44. |
Choose the incorrect statement.A. We are encouraged to plant more trees so as to ensure clean environment and also provide biomass fuel.B. Gobar-gas is produces when crops, vegetable wastes etc., decompose in the absence of oxygen.C. The main ingredient of biogas is ethane and it gives a lot of smoke and also produces a lot of residual ash.D. Biomass is a renewable source of energy. |
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Answer» Correct Answer - C The main ingredient of biogas is methane `(upto 75 %)` and it burns without smoke and leaves no ash. |
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| 45. |
Can any source of energy be pollution-free ? Why or why not ? |
| Answer» No source of enery is totally pollution free-only degree and the manner of pollution varies. A source of energy like a solar cell is pollution free in actual operation but its assembly causes damange to environment. | |
| 46. |
Choose the correct statement.A. Sun can be taken as an inexhaustible source of energy.B. There is infinite storage of fossil fuels inside the Earth.C. Hydro and wind energy plants are non-polluting sources of energyD. Waste form a nuclear power plant can be easily disposed off. |
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Answer» Correct Answer - A Statement ( c) is also correct. However, Hydroelectric power plants damage the environment and fertile land and windmills produce noise-pollution due to continuous whirling and whistling. |
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| 47. |
The power generated in a windmill :A. is more in rainy season since damp air would mean more air mass hitting the bladesB. depends on the height of the towerC. depends on wind velocityD. can be increased by planting tall trees close to the tower |
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Answer» Correct Answer - C The minimum wind velocity for a windmill to function is `15 km//h`. |
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| 48. |
What does a windmill do ? |
| Answer» It converts the kinetic energy of the wind into mechanical or electrical energy. | |
| 49. |
What are the disadvantages of using a solar cooker ? Are there places where solar cookers would have limited utility ? |
| Answer» The solar cookers have limited utility at those places which usually remain cloudy and have long winters. An example of such places are hilly areas. | |
| 50. |
A solar panel containing 1500 solar cell each of surfaces area `5 cm^(2)` arranged in parallel combinations, is used to supply electrical energy for domestic needs. The efficiency of a solar cell is 35% and 600 J of energy is incident on one square metre area in one second, find the electrical energy generated in one hour. |
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Answer» (i) Efficiency =`("Energy utilized")/("Energy supplied ")` (ii) 567 Kj |
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