1. The correct emergent ray has been traced through the figure given in option (b). This is because figure in option (a) depicts no bending of light which is false. The figure in option (c) depicts the bending of light towards the normal ray which is not correct, it should be away from normal. In figurRead more

    The correct emergent ray has been traced through the figure given in option (b). This is because figure in option (a) depicts no bending of light which is false. The figure in option (c) depicts the bending of light towards the normal ray which is not correct, it should be away from normal. In figure (d), only reflection is shown and refraction is not shown. So, the correct answer is: option (b)

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  2. Bacterial cells do not have chloroplast but some photoautotrophic bacteria perform photosynthesis in the presence of chlorophyll incorporated in the cell membrane. Embedded in the cell membrane are reaction centres which absorb light energy. These reaction centres exists in the form of sacs or tubesRead more

    Bacterial cells do not have chloroplast but some photoautotrophic bacteria perform photosynthesis in the presence of chlorophyll incorporated in the cell membrane. Embedded in the cell membrane are reaction centres which absorb light energy. These reaction centres exists in the form of sacs or tubes or sheets depending on the surface area needed. 
    Mitichondria is absent and ribosomes are involved in protein synthesis.

     
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  3. (i) The process that intended for study by this experiment is transpiration. (ii) Transpiration is the process in which water is lost in the form of vapour from the aerial parts of the plant.  (iii) After the experiment, we observe test tube A is raised up i.e., a loss of weight. In test tube B, theRead more

    (i) The process that intended for study by this experiment is transpiration.
    (ii) Transpiration is the process in which water is lost in the form of vapour from the aerial parts of the plant. 
    (iii) After the experiment, we observe test tube A is raised up i.e., a loss of weight. In test tube B, the weight remains unchanged.
    Reason : In test tube A, loses weight due to the plant transpires and loses water. In B there is no plant so there is no transpiration and the oil on the surface prevents direct evaporation and so weight remains unchanged. 
    (iv) As a control experiment. 
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  4. Power out put = (mgh/t) = (work done)/time p x 100/60 =(1000 x 10 x 100)/1 p = (106 x 10 x 60)/100 = 6 x 105w.

    Power out put = (mgh/t) = (work done)/time

    p x 100/60 =(1000 x 10 x 100)/1

    p = (106 x 10 x 60)/100 = 6 x 105w.

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  5. In the case of candle flame , the object is placed beyond c , that means the image is formed or focused between c and f .in second case the object or sun is at infinity , so the image will be formed at focus.this means the distance between image and lens has decreased in the second case. either we hRead more

    In the case of candle flame , the object is placed beyond c , that means the image is formed or focused between c and f .in second case the object or sun is at infinity , so the image will be formed at focus.this means the distance between image and lens has decreased in the second case. either we have to move the screen towards the lens or the lens towards the screen.
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  6. Single circulation is the process in which blood flows only once through the heart during one heart beat. It is seen in fishes.  Double circulation is the process in which the blood flows twice through the heart during each heart beat. This can be found in all mammals e.g humans.

    • Single circulation is the process in which blood flows only once through the heart during one heart beat. It is seen in fishes. 
    • Double circulation is the process in which the blood flows twice through the heart during each heart beat. This can be found in all mammals e.g humans.
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  7. pH of a solution is a measure of the H+ concentration in a solution. Lesser the pH, more acidic is the solution. Thus, rain water of city B is more acidic.

    pH of a solution is a measure of the H+ concentration in a solution. Lesser the pH, more acidic is the solution. Thus, rain water of city B is more acidic.

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