IIT JEE प्रश्न और उत्तर का अभ्यास करें

प्र: What lives in the winter dies in the summer? 1539 0

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    Plants
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    Animals
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    Icycle
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    None of the above
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उत्तर : 3. "Icycle"
व्याख्या :

Answer: C) Icycle Explanation: An icycle, a hanging spike of ice formed by the freezing of dripping water forms due to cool in winter and dies in summer due to hot.

प्र: Formation of curd from milk is chemical reaction. 2910 0

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    TRUE
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    FALSE Answer & Explanation Answer:
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उत्तर : 1. "TRUE"
व्याख्या :

Answer: A) TRUE Explanation: Milk is converted into curd or yogurt by the process of fermentation. Milk consists of globular proteins called casein.    It is biochemical change because here microorganism named lactobacillus react with milk and turn it to curd. Lactobacillus required favourable condition to grow. For it 37 degree temperature is needed. But sometimes when it does not get favourable condition, then other microorganism react and makes the curd taste different.

प्र: Which of the following is a secondary air pollutant? 1566 0

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    Acid rain
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    SO2
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    CO2
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    Dust particles
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उत्तर : 1. "Acid rain"
व्याख्या :

Answer: A) Acid rain Explanation: Secondary pollutants include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight.   Whereas Primary pollutant are those pollutants that are directly emitted from their sources, like CO2, CO, SO2 as these gases are directly emitted form burning of fossil fuels.   Acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water, sulfuric acid etc.   Hence, Acidrain is a secondary air pollutant.

प्र: How many birthdays does the average person have? 2111 0

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उत्तर :
व्याख्या :

Any person can have only 1 birthday i.e, the day he was born. And every year we celebrate it's anniversaries.

प्र: Ashwin fires two bullets from the same place at an interval of 15 minutes but Rahul sitting in a bus approaching the place hears the second sound 14 minutes 30 seconds after the first. If sound travels at the speed of 330 meter per second, what is the approximate speed of bus? 2833 0

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    330/29 m/s
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    330 x 30 m/s
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    330/14 m/s
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  • 4
    330/900 m/s
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उत्तर : 1. "330/29 m/s"
व्याख्या :

Answer: A) 330/29 m/s Explanation: Second gun shot take 30 sec to reach rahul imples distance between two. given speed of sound = 330 m/s Now, distance = 330 m/s x 30 sec    Hence, speed of the bus = d/t = 330x30/(14x60 + 30) = 330/29 m/s.

प्र: Is a mushroom an autotroph? 1661 0

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    TRUE
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    FALSE
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उत्तर : 2. "FALSE"
व्याख्या :

Answer: B) FALSE Explanation: Mushrooms are heterotrophs. They are not plants or autotrophs.   Every living thing that exists need energy in order to live. This energy ultimately comes from the sun, and only plants, or autotrophs, can directly use this energy to make food. Those organisms that cannot harness the sun's energy are known as heterotrophs.   Mushrooms belong to kingdom Fungi and are heterotrophs because they decompose and consume nutrients from the soil. They are not green so they cannot photosynthesize For this reason, mushrooms and all other fungi are heterotrophs.

प्र: Proteins differ from one another because 2297 0

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    The peptide bonds linking amino acids differ from protein to protein
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    Each protein contains its own unique sequence of sugar molecules
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    The number of nucleotides found in each protein varies from molecule to molecule
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    The sequence of amino acids in the polypeptide chain differs from protein to protein
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उत्तर : 4. "The sequence of amino acids in the polypeptide chain differs from protein to protein"
व्याख्या :

Answer: D) The sequence of amino acids in the polypeptide chain differs from protein to protein Explanation:

प्र: The preamble to our constitution provided that India is 1870 0

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    a sovereign, socialist, secular and democratic republic
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    a sovereign republic with a socialist pattern of society
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    a socialist, secular and democratic republic
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    a sovereign, socialist and democratic republic
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उत्तर : 1. "a sovereign, socialist, secular and democratic republic"
व्याख्या :

Answer: A) a sovereign, socialist, secular and democratic republic Explanation: The Preamble was adopted with the constitution in the constituent assembly.   The Preamble proclaims the solemn resolution of the people of India to constitute India into a 'Sovereign socialist secular democratic republic'.

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