IIT JEE Practice Question and Answer

Q: which of the following are chemical changes? 1572 0

  • 1
    Cooking of Food
    Correct
    Wrong
  • 2
    Digestion of Food
    Correct
    Wrong
  • 3
    Freezing of water
    Correct
    Wrong
  • 4
    Water is heated up
    Correct
    Wrong
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Answer : 1. "Cooking of Food"
Explanation :

Answer: A) A & B Explanation: A) Cooking of Food  ------ Chemical Change B) Digestion of Food ----- Chemical Change C) Freezing of water ----- Physical Change D) Water is heated up ---- Physical Change because here the chemical composition of the substance changes in A & B only.   Since we know that, If the chemical composition is changing then it is a chemical change and if the chemical composition is remaining the same, then it is a physical change.

Q: Why did Feudalism end? 1572 0

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Answer :
Explanation :

Feudalism was the dominant social system in medieval Europe, in which the nobility held lands from the Crown in exchange for military service, and vassals were in turn tenants of the nobles, while the peasants were obliged to live on their lord's land and give him homage, labour, and a share of the produce, notionally in exchange for military protection. Feudalism was a combination of legal and military customs in medieval Europe that flourished between the 9th and 14th centuries.Feudalism was based on the division of land by the king to nobles and vassals in return for their military service under the Feudal Levy. The land was the main source of the economy and was dependent on the peasants who worked on the land. The reasons for the decline of Feudalism during the Medieval period of the Middle Ages included: The Crusades and travel during the Middle Ages opened new trade options to EnglandEngland started to move from land-based economy to a money-based economy.   The Black Death - this reduced the population of England by one third. Labour became a valuable commodity.   The Peasants Revolt - Peasants realized their worth and demanded changes. Charters were granted but ignored by nobles.   More trade saw the growth of more towns.   Peasants moved away from the country into towns they were eventually allowed to buy their freedom.   The land was rented and the rights of lords over labor decreased. Armed men were paid a wage and Medieval warfare was financed by taxes and loansNobles became weaker - the Kings took back their lands and power.   A centralized government was established.

Q: A person's present age is two-fifth of the age of his mother. After 8 years, he will be one-half of the age of his mother. How old is the mother at present ? 1572 0

  • 1
    36 yrs
    Correct
    Wrong
  • 2
    38 yrs
    Correct
    Wrong
  • 3
    40 yrs
    Correct
    Wrong
  • 4
    42 yrs
    Correct
    Wrong
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Answer : 3. "40 yrs"
Explanation :

Answer: C) 40 yrs Explanation: Let the mother's present age be x years. Then, the person's present age = 2/5 x years. (2x/5 + 8) = 1/2 (x + 8) 2(2x + 40) = 5(x + 8) => x = 40.

Q: Lasya invested certain amount for two rates of simple interests at 5% p.a. and 4% p.a. What is the ratio of Lasya's investments if the interests from those investments are equal ? 1572 0

  • 1
    4 : 5
    Correct
    Wrong
  • 2
    5 : 4
    Correct
    Wrong
  • 3
    7 : 6
    Correct
    Wrong
  • 4
    6 : 7
    Correct
    Wrong
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Answer : 1. "4 : 5"
Explanation :

Answer: A) 4 : 5 Explanation: Let x be the investment of Lasya in 5% and y be in 4% x(5)(n)/100 = y(4)(n)/100 => x/y = 4/5 x : y = 4 : 5

Q: Diego Garcia is 1572 0

  • 1
    An Island
    Correct
    Wrong
  • 2
    A Country
    Correct
    Wrong
  • 3
    An Ocean
    Correct
    Wrong
  • 4
    None
    Correct
    Wrong
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Answer : 4. "None"
Explanation :

Answer: D) None Explanation: Diego Garcia is a chain of Islands in the Indian ocean with large military base under British Indian Ocean Territory. The U.S. military facility on the island of Diego Garcia in the Indian Ocean represents a horrific example of the human costs of war and imperialism.

Q: What always works with something in its eye? 1572 0

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Answer :
Explanation :

A Needle works when it has thread in its eye that is in its tiny hole.

Q: What value will come in place of question mark (?) in the number - series given below  ?  4, 30, ?, 1440, 7195, 71940 1571 0

  • 1
    145
    Correct
    Wrong
  • 2
    545
    Correct
    Wrong
  • 3
    650
    Correct
    Wrong
  • 4
    999
    Correct
    Wrong
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Answer : 1. "145"
Explanation :

Answer: A) 145 Explanation: 4       30       ?     1440       7195      71940   Here the given series follows a pattern of   4   4 x 10 - 10 = 30   30 x 5 - 5  = 145   145 x 10 - 10 = 1440   1440 x 5 - 5 = 7195   7195 x 10 - 10 = 71940   Hence, the missing number is 145

Q: What temperature is considered freezing? 1571 0

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Answer :
Explanation :

We have all been taught that water freezes at 32 degrees Fahrenheit, 0 degrees Celsius, 273.15 Kelvin. That's not always the case, though. Scientists have found liquid water as cold as -40 degrees F in clouds and even cooled water down to -42 degrees F in the lab.

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