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ScienceClass 10CBSE

1. The decomposers in an ecosystem (a) convert inorganic material, to simpler forms (b) convert organic material to inorganic forms (c) convert inorganic materials into organic compounds do not breakdown organic compounds

Soln: Answer is (b) convert organic material to inorganic forms

ScienceClass 10CBSE

1. What will happen if deer is missing in the food chain given below? Grass → Deer → Tiger (a) The population of tiger increases (b) The population of grass decreases (c) Tiger will start eating grass The population of tiger decreases and the population of grass increases

Soln: Answer is (d) The population of tiger decreases and the population of grass increases. Explanation: Lack of predators will increase population of grass. Population of tiger will reduce due to lack of food.

ScienceClass 10CBSE

1. The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about (a) 1 % (b) 5 % (c) 8 % (d) 10 %

Answer is (a) 1 % Explanation: Green plants utilize 1% of radiation absorbed by leaf and use it for photosynthesis.

ScienceClass 10CBSE

1. Which group of organisms are not constituents of a food chain? (i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and (iii) (i) and (iv)

Soln: Answer is (c) (ii) and (iii) Explanation: In option ii) plankton does not eat grass. In option iii) none of them eat grass hence option c) is the right answer.

ScienceClass 10CBSE

1. Which of the statement is incorrect? (a) All green plants and blue green algae are producers (b) Green plants get their food from organic compounds (c) Producers prepare their own food from inorganic compounds Plants convert solar energy into chemical energy

Soln: Answer is (b) Green plants get their food from organic compounds Explanation: Green plants produce their food by harnessing solar energy. Solar energy is used to prepare carbohydrate with the help of CO2 and water which are in-organic substances.

ScienceClass 10CBSE

1. Which of the following limits the number of trophic levels in a food chain? (a) Decrease in energy at higher trophic levels (b) Sufficient food supply (c) Polluted air Water

Soln: Answer is (a) Decrease in energy at higher trophic levels Explanation: Available energy level at a particular trophic level is 10 times the energy level at next tropic level. When we reach fourth trophic level; a minute portion of energy from producer is available.

ScienceClass 10CBSE

1. In the following groups of materials, which group (s) contains only non-biodegradable items? (i) Wood, paper, leather (ii) Polythene, detergent, PVC (iii) Plastic, detergent, grass (iv) Plastic, bakelite, DDT (a) (iii) (b) (iv) (c) (i) and (iii) (ii) and (iv)

Soln: Answer is (d) (ii) and (iv) Explanation: Group i) has wood and leather which are biodegradable. Group iii) has grass which is biodegradable hence the answer is d) (ii) and (iv)

ScienceClass 10CBSE

1. Excessive exposure of humans to U V-rays results in (i) damage to immune system (ii) damage to lungs (iii) skin cancer (iv) peptic ulcers (a) (i) and (ii) (b) (ii) and (iv) (c) (i) and (iii) (iii) and (iv)

Soln: Answer is (c) (i) and (iii) Explanation: UV rays affect upper surface our body. UV rays lead to skin cancer and effect on skin will affect our immune system as skin is considered as primary level of immune barrier.

ScienceClass 10CBSE

1. Flow of energy in an ecosystem is always (a) unidirectional (b) bidirectional (c) multi directional no specific direction

Soln: Answer is (a) unidirectional Explanation: Flow of energy is from prey to predator and it cannot be in reverse direction . Hence flow of enrgy is uni- directional.

ScienceClass 10CBSE

1. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the (a) food web (b) ecological pyramid (c) ecosystem food chain

Soln: Answer is (a) Food Web

ScienceClass 10CBSE

1. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of (a) heat energy (b) light energy (c) chemical energy mechanical energy

Soln: Answer is (c) chemical energy Explanation: Energy is available for transfer from one trophic level to the next in the form of food. Food is a chemical form of energy.

ScienceClass 10CBSE

1. Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called (a) decomposers (b) producers (c) herbivores carnivores

Soln: Answer is (b) producers Explanation: Producers use solar energy to synthesize food from water and carbon-di-oxide. Plants and few micro-organisms are the producers. Organisms that decompose organic material are called decomposers. Herbivores are the organisms that feed on plant and its products. Carnivore are the ones which feed on other organisms.

ScienceClass 10CBSE

1. Depletion of ozone is mainly due to (a) chlorofluorocarbon compounds (b) carbon monoxide (c) methane pesticides

Soln: Answer is (a) chlorofluorocarbon compounds

ScienceClass 10CBSE

1. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as (a) eutrophication (b) pollution (c) biomagnification accumulation

Soln: Answer is (c) biomagnification Explanation: Eutrophication is richness of nutrient beyond optimum Eutrophication occurs due to run off from land. Introduction of an undesired substance into Pollution leads to harmful effects on living organisms.

ScienceClass 10CBSE

1. In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level? Grass → Grasshopper → Frog → Snake → Hawk (a) 5 k J (b) 50 k J (c) 500 k J (d) 5000 k J

Soln: Answer is (d) 5000 k J Explanation: Available energy level at a particular trophic level is 10 times the energy level at next tropic level. Hence, energy at third level trophic level is 50kj. Second level trophic has 500 KJ energy and 1st level trophic level (Producer) has energy of 5000 KJ.

ScienceClass 10CBSE

1. An ecosystem includes (a) all living organisms (b) non-living objects (c) both living organisms and non-living objects sometimes living organisms and sometimes non-living objects

Soln: Answer is (c) both living organisms and non-living objects Explanation: An ecosystem is a complex of living and nonliving organisms and their interactions.

ScienceClass 10CBSE

1. In a food chain, the third trophic level is always occupied by (a) carnivores (b) herbivores (c) decomposers producers

Soln: Answer is (a) carnivores Explanation: First trophic level are producers, second tropic level are herbivores, third trophic level is occupied by carnivores.

ScienceClass 10CBSE

1. Which one of the following is an artificial ecosystem? (a) Pond (b) Crop field (c) Lake (d) Forest

Soln: Answer is (b) Crop field Explanation: Crop field is a man made ecosystem.

ScienceClass 10CBSE

1. An organic compound A on heating with concentrated H2 SO4 forms a compound B which on addition of one mole of hydrogen in presence of Ni forms a compound C. One mole of compound C on combustion forms two moles of CO2 and 3 moles of H2O. Identify the compounds A, B and C and write the chemical equations of the reactions involved.

Soln: Compound A is Ethanol Compound A = CH3CH2OH CH3CH2OH conc. H2SO4 CH2-CH2+ H2O Compound B is Ethane Compound B = CH2= CH2 CH2=CH2 Ni C2H6 Compound C = CH3 — CH3 2C2H6+7O2 4CO2 +6H2O

ScienceClass 10CBSE

1. Explain the given reactions with the examples (a) Hydrogenation reaction (b) Oxidation reaction (c) Substitution reaction (d) Saponification reaction (e) Combustion reaction

Addition of Hydrogen to unsaturated Hydrocarbons to convert into saturated Hydrocarbons is called as Hydrogenation. This process is used in the conversion of unsaturated vegetable oil into saturated fats. R2C+CR+H2 Ni R2C-CR2 H H When oxygen is added to alcohol to form carboxylic acid the process is known as Ex: CH3CH2CH2OH Alk KMnO4/ acidified K2Cr2O7 CH3CH2COOH Saturated hydrocarbons are fairly But in the presence of sunlight chlorine substitutes Hydrogen one by one. Ex: CH4+Cl2 CH3Cl+HCl( In presence of sunlight) When Ester is treated with alkali, the reaction gives ethanol and Sodium This reaction is called saponification. Ex: CH3COOC2H5+NaOH CH3COONa+C2H5OH Combustion is the burning of a substance in presence of Ex: CH4+O2 CO2+H2O+ heat and Light

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Filtered results

1. The decomposers in an ecosystem (a) convert inorganic material, to simpler forms (b) convert organic material to inorganic forms (c) convert inorganic materials into organic compounds do not breakdown organic compounds

1. What will happen if deer is missing in the food chain given below? Grass → Deer → Tiger (a) The population of tiger increases (b) The population of grass decreases (c) Tiger will start eating grass The population of tiger decreases and the population of grass increases

1. The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about (a) 1 % (b) 5 % (c) 8 % (d) 10 %

1. Which group of organisms are not constituents of a food chain? (i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and (iii) (i) and (iv)

1. Which of the statement is incorrect? (a) All green plants and blue green algae are producers (b) Green plants get their food from organic compounds (c) Producers prepare their own food from inorganic compounds Plants convert solar energy into chemical energy

1. Which of the following limits the number of trophic levels in a food chain? (a) Decrease in energy at higher trophic levels (b) Sufficient food supply (c) Polluted air Water

1. In the following groups of materials, which group (s) contains only non-biodegradable items? (i) Wood, paper, leather (ii) Polythene, detergent, PVC (iii) Plastic, detergent, grass (iv) Plastic, bakelite, DDT (a) (iii) (b) (iv) (c) (i) and (iii) (ii) and (iv)

1. Excessive exposure of humans to U V-rays results in (i) damage to immune system (ii) damage to lungs (iii) skin cancer (iv) peptic ulcers (a) (i) and (ii) (b) (ii) and (iv) (c) (i) and (iii) (iii) and (iv)

1. Flow of energy in an ecosystem is always (a) unidirectional (b) bidirectional (c) multi directional no specific direction

1. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the (a) food web (b) ecological pyramid (c) ecosystem food chain

1. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of (a) heat energy (b) light energy (c) chemical energy mechanical energy

1. Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called (a) decomposers (b) producers (c) herbivores carnivores

1. Depletion of ozone is mainly due to (a) chlorofluorocarbon compounds (b) carbon monoxide (c) methane pesticides

1. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as (a) eutrophication (b) pollution (c) biomagnification accumulation

1. In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level? Grass → Grasshopper → Frog → Snake → Hawk (a) 5 k J (b) 50 k J (c) 500 k J (d) 5000 k J

1. An ecosystem includes (a) all living organisms (b) non-living objects (c) both living organisms and non-living objects sometimes living organisms and sometimes non-living objects

1. In a food chain, the third trophic level is always occupied by (a) carnivores (b) herbivores (c) decomposers producers

1. Which one of the following is an artificial ecosystem? (a) Pond (b) Crop field (c) Lake (d) Forest

1. Explain the given reactions with the examples (a) Hydrogenation reaction (b) Oxidation reaction (c) Substitution reaction (d) Saponification reaction (e) Combustion reaction

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