31). Assertion (A) : Wet sand looks darker than dry sand. Reason (R ) : Water is opaque to visible light.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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32). Assertion (A) : Forests play a role in retaining sub-soil water. Reason (R ) : Forests add humus to the soil.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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33). Assertion (A) : Some birds eat small stones with the grains. Reason (R ) : The stones eaten by birds accumulate in the gizzard and facilitate the grinding process and thus help digestion.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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34). Assertion (A) : If the earth did not have an atmosphere, its average surface temperature would be lower than what it is. Reason (R ) : The ozone layer in the atmosphere absorbs the ultraviolet radiation.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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35). Assertion (A) : A gas thermo0meteer is more sensitive than a liquid thermometer. Reason (R ) : Gases can be heated to high temperatures whereas liquids vaporise at a particular temperature.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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36). Assertion (A) : When light travels from a denser to a rarer medium, it loses speed but not energy. Reason (R ) : Energy carried by a wave depends on the amplitude and not the speed of wave propagation.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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37). Assertion (A) : It is easier to start a car engine one a warm day that on a chilly day. Reason (R ) : The internal resistance of a car battery increases with increase in temperature.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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38). Assertion (A) : Catalytic convertors are specifically for use in automobiles using leaded petrol. Reason (R ) : Catalytic converters convert harmful exhaust gases into carbon dioxide, steam and nitrogen.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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39). Assertion (A) : The growth of rice plant is better when it is cultivated along with blue-green algae. Reason (R ) : Blue-green algae increase the soil fertility through nitrogen fixation.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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40). Assertion (A) : The nucleus is the central dense part of an atom. Reason (R ) : The nucleus is composed of positively charged protons and negatively charged electrons.
A). Both A and R are true and R is the correct explanation of A. |
B). Both A and R are true but R is not the correct explanation of A.. |
C). A is true but R is false. |
D). A is false but R is true. |
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