Cultivation practices and crop yield
Question: Cultivation practices and crop yield are related to environmental conditions. Explain. Solution: All crops do not grow under similar conditions. Some require high temperature, some low temperature, longer duration of sunlight, shorter duration of sunlight, more humidity, low humidity, moderate humidity, loam soil, sandy soil, etc. Apple cannot be grown in plains because it requires several days of low temperature. In plains, there are two major seasons of crop plants kharif (rainy seas...
Read More →Fill in the blanks :
Question: Fill in the blanks : (a) Photoperiod affect the . . (b) Kharif crops are cultivated from .. to .. . (c) Rabi crops are cultivated from to .. . (d) Paddy, Maize, Green Gram and Black Gram are .. crops. (e) Wheat, Gram, Pea and Mustard are . crops. Solution: (a) flowering (of plants) (b) June, October (c) November, April (d) kharif (e) rabi....
Read More →Define the terms hybridisation and photoperiod.
Question: Define the terms hybridisation and photoperiod. Solution: Hybridisation. It is crossing of two (or more) types of individuals with different useful traits in order to bring them together in the progeny. Photoperiod. It is duration of day light that influences plants and other organisms in their growth, reproduction and maturation....
Read More →Group the following and tabulate them as energy yielding,
Question: Group the following and tabulate them as energy yielding, protein yielding, oil yielding and fodder crop : Wheat, Rice, Berseem, Maize, Gram, Oat, Pigeon Gram, Sudan Grass, Lentil, Soyabean, Groundnut, Castor and Mustard. Solution: 1. Wheat, Rice, Maize, Oat Energy yielding. 2. Gram, Pigeon Gram, Lentil, Soyabean Protein yielding. 3. Ground nut, Castor, Mustard, Soyabean Oil yeilding. 4. Berseem, Oat, Sudan Grass Fodder crops....
Read More →If there is low rainfall in a village throughout the year,
Question: If there is low rainfall in a village throughout the year, what measures will you suggest to the farmers for better cropping. Solution: 1. Reduced tilling 2. Enrich soil with humus which increases its water holding capacity 3. Use of drought resistant and early maturing varieties of crops....
Read More →Match the columns A and B.
Question: Match the columns $A$ and $B$. Solution: $a-i i i$, $b-v$, $c-i v$, $d-i$, $e-i i .$...
Read More →Give one word for the following :
Question: Give one word for the following : (a) Farming without the use of chemicals as fertilizers, herbicides and pesticides is known as .. . (b) Growing of Wheat and Groundnut on the same field is called . (c) Planting of Soyabean and Maize in alternate rows in the same field is called as . (d) Growing different crops on a piece of land in pre-planned succession is known as .. . (e) Xanthium and Parthenium are commonly known as . . (f) Causal organism of any disease is called as . . Solution:...
Read More →Why is use of excess fertilizer
Question: Why is use of excess fertilizer detrimental for environment? Solution: Use of excess fertilisers will cause : 1. Mineral loading of underground water. 2. Excess minerals in the crop plants. 3. Salination of soil. 4. Run off from fertilizers rich soil, will cause eutrophication of water bodies....
Read More →Why is organic matter important for crop production ?
Question: Why is organic matter important for crop production ? Solution: Organic matter forms humus. It is important for crop production because it makes the soil fertile. 1. Organic matter improves soil structure by forming soil crumbs. 2. It increases water holding capacity of sandy soils. 3. It improves aeration of clayey soils. 4. During its decomposition, it liberates minerals which enrich the soil. 5. Biochemicals present in decaying organic matter improve growth of crop plants....
Read More →List out some useful traits in improved crop.
Question: List out some useful traits in improved crop. Solution: 1. Higher yield 2. Improved quality 3. Resistance to biotic and abiotic stresses 4. Change in maturity 5. Wider adaptability 6. Desirable agronomic traits....
Read More →What is GM crop?
Question: What is GM crop? Name any one crop which is grown in India. Solution: GM or genetically modified crop is the one which has been developed through introduction of some specific genes from other sources, e.g, insect resistant B Cotton (being grown in India), vitamin A rich Golden Rice....
Read More →Fill in the blanks
Question: Fill in the blanks (a) Pigeon Pea is a good source of . (b) Berseem is an important . crop. (c) The crops which are grown in rainy season are called .. crops. (d) are rich in vitamins. (e) crop grows in winter seasons. Solution: (a) protein (b) fodder (c) kharif (d) Vegetables (e) Rabi....
Read More →Match the items of column A with those of column B.
Question: Match the items of column A with those of column B. Solution: $a-i i$, $b-i i i$, $c-i$, $d-i v .$...
Read More →Evaluate the following determinant:
Question: Evaluate the following determinant: (i) $\left|\begin{array}{ccc}1 3 5 \\ 2 6 10 \\ 31 11 38\end{array}\right|$ (ii) $\left|\begin{array}{lll}67 19 21 \\ 39 13 14 \\ 81 24 26\end{array}\right|$ (iii) $\left|\begin{array}{lll}a h g \\ h b f \\ g f c\end{array}\right|$ (iv) $\left|\begin{array}{ccc}1 -3 2 \\ 4 -1 2 \\ 3 5 2\end{array}\right|$ (v) $\left|\begin{array}{ccc}1 4 9 \\ 4 9 16 \\ 9 16 25\end{array}\right|$ (vi) $\left|\begin{array}{ccc}6 -3 2 \\ 2 -1 2 \\ -10 5 2\end{array}\rig...
Read More →Carbon dioxide is necessary for plants.
Question: Carbon dioxide is necessary for plants. Why do we consider it as a pollutant? (CCE 2014) Solution: Besides being essential for photosynthesis, carbon dioxide is a green house gas. Upto $350 \mathrm{ppm}$, it is both a good raw material as well as essential for keeping the earth warm. However, when its concentration rises (as presently it is $400 \mathrm{ppm}$ ), it becomes pollutant because it results in global warming. The latter is quite dangerous because it will melt polar ice, rais...
Read More →Explain the role of the sun in the formation of soil.
Question: Explain the role of the sun in the formation of soil. Solution: Paedogenesis: It is the process of formation of soil from rocky crust of earth. Paedogenesis occurs in two stages, weathering and humification. 1. Weathering It is the process of breaking down of rock present on the surface of earth into fine particles. Weathering is caused by three types of processes - physical, chemical and biological. Physical weathering is pulverisation of rocky matter caused by physical phenomena like...
Read More →Justify "Dust is a pollutant."
Question: Justify "Dust is a pollutant." (CCE 2012) Solution: 1. Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold, 2. Dust reduces light intensity, 3. Its particles are eye irritants, 4. Dust settles over plant foliage and reduces photosynthetic activity, 5. Dust particles block stomata reducing gaseous exchange, 6. Dust particles can pick up toxic metals and chemicals being emitted by indus...
Read More →A motor car, with its glass totally closed,
Question: A motor car, with its glass totally closed, is parked directly under the sun. The inside temperature of the car rises very high. Explain why? (CCE 2012) Solution: Glass is transparent to sunlight, allowing it to pass into the interior of the car. It heats up the interior. But heat waves do not escape from the car due to glass being opaque to the same. As a result, the interior of the car placed in the sun will become very hot. It is similar to glass house effect....
Read More →What are the causes of water pollution?
Question: What are the causes of water pollution? Discuss how you can contribute in reducing water pollution? Solution: Causes of Water Pollution: 1. $21 \%$ of all infectious diseases and $66 \%$ of all deaths of children below 5 years are caused by contamination of drinking and bathing water by pathogens present in sewage, e.g., cholera, typhoid, diarrhoea, dysentery, jaundice, etc. 2. Toxic Chemicals: Industrial effluents pass down a number of toxic chemicals, g., mercury by paper industry (m...
Read More →For what value of $x$ the matrix $A$ is singular?
Question: For what value of $x$ the matrix $A$ is singular? $(\mathrm{i}) A=\left[\begin{array}{ll}1+x 7 \\ 3-x 8\end{array}\right]$ (ii) $A=\left[\begin{array}{ccc}x-1 1 1 \\ 1 x-1 1 \\ 1 1 x-1\end{array}\right]$ Solution: (i) Matrix $A$ will be singular if $|A|=0$ $|A|=\left|\begin{array}{ll}1+x 7 \\ 3-x 8\end{array}\right|=0$ $\Rightarrow 8+8 x-21+7 x=0$ $\Rightarrow 15 x-13=0$ $\Rightarrow 15 x=13$ $\Rightarrow x=\frac{13}{15}$ (ii) MatrixAwill be singular if $|A|=0$ $\Rightarrow(x-1)\left[(...
Read More →For what value of $x$ the matrix $A$ is singular?
Question: For what value of $x$ the matrix $A$ is singular? $(\mathrm{i}) A=\left[\begin{array}{ll}1+x 7 \\ 3-x 8\end{array}\right]$ (ii) $A=\left[\begin{array}{ccc}x-1 1 1 \\ 1 x-1 1 \\ 1 1 x-1\end{array}\right]$ Solution: (i) Matrix $A$ will be singular if $|A|=0$ $|A|=\left|\begin{array}{ll}1+x 7 \\ 3-x 8\end{array}\right|=0$ $\Rightarrow 8+8 x-21+7 x=0$ $\Rightarrow 15 x-13=0$ $\Rightarrow 15 x=13$ $\Rightarrow x=\frac{13}{15}$ (ii) MatrixAwill be singular if $|A|=0$ $\Rightarrow(x-1)\left[(...
Read More →How do fossil fuels cause air pollution ?
Question: How do fossil fuels cause air pollution ? (CCE 2012) Solution: Fossil fuels (coal, petroleum) are burnt to obtain energy. Combustion produces 1. Suspended particles 2. Sulphur oxides 3. Nitrogen oxides 4. Carbon monoxide 5. Vapours of hydrocarbons. All these are air pollutants. Hydrocarbons are a source of cancer. They also damage internal organs. Alongwith nitrogen oxides, they produce ozone and smog. Sulphur and nitrogen oxides give rise to acid rain. They are also irritants and dama...
Read More →Why are root nodules
Question: Why are root nodules useful for the plants? (CCE 2012) Solution: Root nodules mostly occur in legume plants. These nodules contain nitrogen fixing bacteria named Rhizabium. The bacteria pick up nitrogen from soil atmosphere and convert it into organic compounds. The same pass into plant so that legumes become rich in proteins and other nitrogen compounds....
Read More →Find the integral value of x
Question: Find the integral value of $x$, if $\left|\begin{array}{ccc}x^{2} x 1 \\ 0 2 1 \\ 3 1 4\end{array}\right|=28$ Solution: Given : $\left|\begin{array}{ccc}x^{2} x 1 \\ 0 2 1 \\ 3 1 4\end{array}\right|=28$ $\Rightarrow x^{2}(8-1)-x(0-3)+1(0-6)$ $\Rightarrow 8 x^{2}-x^{2}+3 x-6=28$ $\Rightarrow 7 x^{2}+3 x-6=28$ $\Rightarrow 7 x^{2}+3 x-34=0$ $\Rightarrow(7 x+17)(x-2)=0$ $\Rightarrow x=2$ Integral value of $x$ is 2 . Thus, $x=\frac{-17}{7}$ is not an integer....
Read More →Why step farming is common in hills?
Question: Why step farming is common in hills? Solution: Step farming or terracing is carried out in the hills because it slows down the speed of rain water currents, checks soil erosion and increases water absorption by soil....
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