IIT JEE प्रश्न और उत्तर का अभ्यास करें

प्र: A Sarcomere is the distance between two 1757 0

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    Z discs
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    H zones
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    A bands
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    I bands
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उत्तर : 1. "Z discs"
व्याख्या :

Answer: A) Z discs Explanation: A sarcomere is the basic unit of striated muscle tissue. It is the repeating unit between two Z lines. Skeletal muscles are composed of tubular muscle cells (myocytes called muscle fibers or myofibers) which are formed in a process known as myogenesis. Muscle fibers contain numerous tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as alternating dark and light bands. Sarcomeres are composed of long, fibrous proteins as filaments that slide past each other when a muscle contracts or relaxes.   A muscle fiber from a biceps muscle may contain 100,000 sarcomeres.

प्र: Why are hydrocarbons insoluble in water? 1361 0

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उत्तर :
व्याख्या :

We know that polar substances are soluble in polar solvents and non polar substances are soluble in non-polar solvents only. Here the hydrocarbons are non-polar molecular substances and water is a polar solvent. So water can't dissolve hydrocabons.   Hence, as hydrocarbons are non-polar substances, they are insoluble in water as it is a highly polar solvent.

प्र: A hybrid of a donkey and a horse 1666 0

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    Panthera and Mule
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    Mules and Hinnys
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    Liger and Hinnys
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    Wholphin and Mule
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उत्तर : 2. "Mules and Hinnys"
व्याख्या :

Answer: B) Mules and Hinnys Explanation: Donkeys and horses can be breed to make mules and hinnys. A hinny is a domestic equine hybrid that is the offspring of a male horse, a stallion, and a female donkey, a jenny. It is the reciprocal cross to the more common mule, which is the product of a male donkey, a jack, and a female horse, a mare.

प्र: What are the sides of the dna ladder made of 1458 0

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    nitrates and sugars
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    sugars and hydrates
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    sugars and phosphates
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    phosphates and nitrates
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उत्तर : 3. "sugars and phosphates"
व्याख्या :

Answer: C) sugars and phosphates Explanation: DNA is a double-stranded molecule twisted into a helix. The shape of DNA is a double helix, which is like a twisted ladder. The sides of the ladder are made of alternating sugar and phosphate molecules. Deoxyribose, which is a pentose, and a phosphate group are the two molecules together form the two sides of the DNA. The rungs of the ladder are pairs of 4 types of nitrogen bases.

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उत्तर :
व्याख्या :

Given A,B,C can complete a work in 15,20 and 30 respectively. The total work is given by the LCM of 15, 20, 30 i.e, 60. A's 1 day work = 60/15 = 4 units B's 1 day work = 60/20 = 3 units C's 1 day work = 60/30 = 2 units (A + B + C) worked for 2 days = (4 + 3 + 2) 2 = 18 units  Let B + C worked for x days = (3 + 2) x = 5x units C worked for 2 days = 2 x 2 = 4 units Then, 18 + 5x + 4 = 60 22 + 5x = 60 5x = 38 x = 7.6   Therefore, total number of days taken to complete the work = 2 + 7.6 + 2 = 11.6 = 11 3/5 days.

प्र: 30% of 500 rupees is? 1638 0

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    Rs. 180
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    Rs. 150
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    Rs. 120
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    Rs. 240
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उत्तर : 2. "Rs. 150"
व्याख्या :

Answer: B) Rs. 150 Explanation: Given 30% of 500 = 30100 x 500= 30 x 5= 150   Hence, 30% of Rs. 500 = Rs. 150.

प्र: Dry ice is an example of which process 1824 0

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    Condensation
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    Evaporation
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    Sublimation
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    Freezing
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उत्तर : 3. "Sublimation"
व्याख्या :

Answer: C) Sublimation Explanation: Sublimation is a process when a solid changes directly into gas instead changing into liquid first. Dry ice is an example of Sublimation process because it doesn't change into liquid CO2 and directly change into gaseous CO2 when heated.   Hence, Dry ice is an example of Sublimation process.

प्र: Simplify 39.96% of 649.85 ÷13.07 = 45.14 - ? 1692 0

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    25
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    26
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    27
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    28
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उत्तर : 1. "25"
व्याख्या :

Answer: A) 25 Explanation: This can be easily simplified by Approximation process Given 39.96% of 649.85 ÷13.07 = 45.14 - ? can be written as  40% of 650 ÷13 = 45 - ?   40 x 65010013 = 45 - ?? = 45 - 20? = 25.

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