Green colour of leaves is due
Question: Green colour of leaves is due to the presence of the pigment (a) chlorophyll (b) mitochondria (c) ribosomes (d) chloroplast Solution: (a) The pigment chlorophyll present in the chloroplasts, which is responsible for green colour of leaves. It can absorb solar energy for photosynthesis....
Read More →If there is an error of a% in measuring the edge of a cube, then percentage error in its surface is
Question: If there is an error of a% in measuring the edge of a cube, then percentage error in its surface is (a) $2 a \%$ (b) $\frac{a}{2} \%$ (c) $3 a \%$ (d) none of these Solution: (a) 2a% Letxbe the side of the cube andybe its surface area. $\frac{\Delta x}{x} \times 100=a$ Also, $y=6 x^{2}$ $\Rightarrow \frac{d y}{d x}=12 x$ $\Rightarrow \frac{\Delta y}{y}=\frac{12 x}{y} \times d x=\frac{2}{x} \times \frac{a x}{100}$ $\Rightarrow \frac{\Delta y}{y} \times 100=2 a$ Hence, the error in the s...
Read More →Choose the correct statements.
Question: Choose the correct statements. (a) Genes are located in the chromosomes (b) Cell is located in the nucleus (c) Chromosomes are located in the nucleolus (d) Cell membrane surrounds the nucleus Solution: (a) Genes are the unit of inheritance located in the chromosomes. The other statements are incorrect and their correct form are as: Nucleus is located in the cell Chromosomes are located in the nucleus. Cell membrane surrounds the cell and nuclear membrane surrounds the nucleus....
Read More →If there is an error of a% in measuring the edge of a cube, then percentage error in its surface is
Question: If there is an error of a% in measuring the edge of a cube, then percentage error in its surface is (a) $2 a \%$ (b) $\frac{a}{2} \%$ (c) $3 a \%$ (d) none of these Solution: (a) 2a% Letxbe the side of the cube andybe its surface area. $\frac{\Delta x}{x} \times 100=a$ Also, $y=6 x^{2}$ $\Rightarrow \frac{d y}{d x}=12 x$ $\Rightarrow \frac{\Delta y}{y}=\frac{12 x}{y} \times d x=\frac{2}{x} \times \frac{a x}{100}$ $\Rightarrow \frac{\Delta y}{y} \times 100=2 a$ Hence, the error in the s...
Read More →Read the following terms and select
Question: Read the following terms and select the pair that is related to inheritance of characters. (a) cell wall and cell membrane (b) chromosome and mitochondria (c) chloroplast and cell membrane (d) chromosome and genes Solution: (d) Chromosomes and genes are related to inheritance of characters.Chromosomes are present in nucleus. They contain genes, which are unit of inheritance....
Read More →Read the following pair§ of examples
Question: Read the following pair of examples of organisms. (a) Moss and sponge (b) Yeast and Amoeba (c) Bacteria and blue-green algae (d) Penicillium and Spirogyra The pair that belongs to the group of prokaryotes is Solution: (c) Bacteria and blue-green algae are examples of prokaryotes. These organisms consist of prokaryotic cell (no nuclear membrane, no well defined nucleus and no other cell organelles....
Read More →The jelly-like substance present in
Question: The jelly-like substance present in cells is called (a) protoplasm (b) chloroplast (c) chromosome (d) cytoplasm Solution: (c) Cytoplasm is the transparent jelly like fluid which fills the cell between nucleus and cell membrane. Most of the chemical reactions which keep the cell alive takes place here.Protoplasm is the living substance of the cell. It includes the cytoplasm and nucleus. Chromoplasts are coloured plastids present in plant cell.Chromosomes are thread-like structures prese...
Read More →If there is an error of 2% in measuring the length of a simple pendulum, then percentage error in its period is
Question: If there is an error of 2% in measuring the length of a simple pendulum, then percentage error in its period is (a) $1 \%$ (b) $2 \%$ (c) $3 \%$ (d) $4 \%$ Solution: (a) 1%Letlbe the length if the pendulum andTbe the period. Also, let $\Delta l$ be the error in the length and $\Delta T$ be the error in the period. We have $\frac{\Delta l}{l} \times 100=2$ $\Rightarrow \frac{d l}{l} \times 100=2$ Now, $T=2 \pi \sqrt{\frac{1}{g}}$ Taking log on both sides, we get $\log T=\log 2 \pi+\frac...
Read More →If there is an error of 2% in measuring the length of a simple pendulum, then percentage error in its period is
Question: If there is an error of 2% in measuring the length of a simple pendulum, then percentage error in its period is (a) $1 \%$ (b) $2 \%$ (c) $3 \%$ (d) $4 \%$ Solution: (a) 1%Letlbe the length if the pendulum andTbe the period. Also, let $\Delta l$ be the error in the length and $\Delta T$ be the error in the period. We have $\frac{\Delta l}{l} \times 100=2$ $\Rightarrow \frac{d l}{l} \times 100=2$ Now, $T=2 \pi \sqrt{\frac{1}{g}}$ Taking log on both sides, we get $\log T=\log 2 \pi+\frac...
Read More →A suitable term for the various
Question: A suitable term for the various components of cells is (a) tissue (b) cell organelles (c) chromosomes (d) genes Solution: (b) Various components of cells are called cell organelles. Tissue is a group of similar cells which worktogether to perform a particular function. Also, Refer to Ans 3....
Read More →Which one of the following terms
Question: Which one of the following terms is not a part of the nucleus? (a) Ribosome (b) Nucleolus (c) Chromosome (d) Gene Solution: (a) Ribosome is not a part of nucleus. They are found floating in the cytosol or attached to the endoplasmic reticulum. Nucleus is the largest organelle in cell that contain thread-like structures called chromosomes on which genes are present. Nucleolus is the round irregular structures present inside nucleus....
Read More →Read the different combinations
Question: Read the different combinations of terms given below: (a) Cell wall, cell membrane, nucleus, plastid . (b) Cell wall, nucleus, ribosome, chromosome (c) Cell membrane, mitochondria, ribosome, chromosome (d) Cell membrane, ribosome, mitochondria, chloroplast The correct combination of terms with reference to an animal cell is Solution: (c) The correct combination of terms with reference to an animal cell is cell membrane, mitochondria, ribosome and chromosome. An animal cell does not hav...
Read More →Majority of cells cannot be seen
Question: Majority of cells cannot be seen directly with our naked eyes because (a) organisms are generally unicellular (b) cells are microscopic (c) cells are present only inside the body (d) cells are grouped into tissues Solution: (b) A cell is the smallest and basic unit of life which has definite structure and performs a specific function. Most of them cannot be seen with naked eyes because they are microscopic (i.e very-very small)....
Read More →Choose the correct statement
Question: Choose the correct statement with respect to unicellular organisms. (a) In unicellular organisms, tissues work in coordination to perform different functions (b) Unicellular organisms do not require food (c) Unicellular organisms respire and reproduce (d) AH unicellular organisms move by cilia Solution: (c) The organisms which are made of single cell are called unicellular organisms. The single cell behaves as a complete organism performing basic functions such as respiration, reproduc...
Read More →Find the sum of the series:
Question: Find the sum of the series: $\frac{1}{1 \times 2}+\frac{1}{2 \times 3}+\frac{1}{3 \times 4}+\ldots \frac{1}{(2 n-1)(2 n+1)}$ Solution: In the given question we need to find the sum of the series. For that, first, we need to find the $\mathrm{n}^{\text {th }}$ term of the series so that we can use summation of the series with standard identities and get the required sum. The series given is $\frac{1}{1 \times 2}+\frac{1}{2 \times 3}+\frac{1}{3 \times 4} \ldots$ to $\mathrm{n}$ terms. So...
Read More →Why should we save paper?
Question: Why should we save paper? Solution: Paper should be saved because it produces from our important natural resource, i.e. trees (around 17 full grown trees are needed to make one tonne of paper). Therefore, in order to save trees and prevent the impact of their loss on living world, we need to save paper. We can save paper by following ways: 1.Paper should be recycled. 2.Use both side of a paper for writing purpose. . 3.Spread awareness regarding the value of saving paper....
Read More →How does deforestation leads
Question: How does deforestation leads to frequent floods and droughts? Solution: When the forest trees are cut down, then the lesser number of trees put less water vapour into atmosphere through transpiration. Since, less water vapour is put into the atmosphere, there is less rainfall in that area. When there is less rainfall in an area, then less water percolates into the ground. Due to this, the groundwater level also gets lowered. The shortage of surface water (in ponds, lakes, etc) and grou...
Read More →Is deforestation associated
Question: Is deforestation associated with global warming? Explain. Solution: Plants use carbon dioxide gas from the atmosphere for the process of photosynthesis. When a lot of trees are cut down (i.e., deforestation), then lesser number of trees will be left. The lesser number of trees will use up less carbon dioxide due to which the amount of carbon dioxide in the atmosphere will increase. Thus, deforestation increases the level of carbon dioxide in the atmosphere. Carbon dioxide gas traps the...
Read More →What is biodiversity?
Question: What is biodiversity? Solution: Biodiversity or Biological diversity refers to the variety of organisms existing on the earth, their interrelationships and their relationship with the environment....
Read More →Mention the aim of Forest
Question: Mention the aim of Forest (Conservation) Act. Solution: The aim of Forest (Conservation) Act is preservation and conservation of natural forests and meeting the basic needs of the people living in or near the forests....
Read More →What is the unique feature
Question: What is the unique feature of the biodiversity found in Pachmarhi Biosphere Reserve? Solution: The biodiversity found in Pachmarhi Biosphere Reserve is similar to those of the upper Himalayan peaks and to those belonging to the lower Western Ghats. Thus, making it unique....
Read More →Find the sum of the series:
Question: Find the sum of the series: $\frac{1}{1 \times 2}+\frac{1}{2 \times 3}+\frac{1}{3 \times 4}+$ . To n terms Solution: In the given question we need to find the sum of the series. For that, first, we need to find the $\mathrm{n}^{\text {th }}$ term of the series so that we can use summation of the series with standard identities and get the required sum. The series given is $\frac{1}{1 \times 2}+\frac{1}{2 \times 3}+\frac{1}{3 \times 4}+. .$ to $\mathrm{n}$ terms. The series can be writt...
Read More →Does soil erosion affect
Question: Does soil erosion affect the fertility of soil? How? Solution: Yes, soil erosion affects the fertility of the soil. It removes the top layer of soil (i.e. fertile layer) which exposes the hard rocky lower layers which are less fertile....
Read More →A new species X is introduced
Question: A new species X is introduced in a forest. How is it likely to affect the local species of that area? Solution: The new species is likely to affect the local species as it poses threats in following manner: 1. Preying on native species. 2. Increasing competition for food or other resources. 3. Cadsing or carrying disease. 4. Preventing native species from reproducing. 5. Altering the structure of food webs....
Read More →Find the approximate change in the value V of a cube of side x metres caused by increasing the side by 1%.
Question: Find the approximate change in the valueVof a cube of sidexmetres caused by increasing the side by 1%. Solution: Volume of the cube, $V=x^{3}$ We have $\Delta x=0.01 x$ $\frac{d V}{d x}=3 x^{2}$ $\Rightarrow \Delta V=d V=\frac{d V}{d x} d x=3 x^{2} \times 0.01 x=0.03 x^{3}$ Hence, the approximate change in the value $V$ of the cube is $0.03 x^{3} \mathrm{~m}^{3}$. Disclaimer: This solution has been created according to the question given in the book. However, the solution in the book i...
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