IIT JEE प्रश्न और उत्तर का अभ्यास करें

प्र: Two trains are moving in the same direction at 72 kmph and 36 kmph. The faster train crosses a girl sitting at window seat in the slower train in 32 seconds. Find the length of the faster train ? 5351 0

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    170 m
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    100 m
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    270 m
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  • 4
    320 m
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उत्तर : 4. "320 m"
व्याख्या :

Answer: D) 320 m Explanation: Relative speed = (72 - 36) x 5/18 = 2 x 5 = 10 mps.Distance covered in 32 sec = 32 x 10 = 320 m. The length of the faster train = 320 m.

प्र: Who translated Ramayana into Persian? 5347 0

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    Abdul Fazi
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    Badauni
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  • 3
    Isar Das
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  • 4
    Abdul Latif
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उत्तर : 1. "Abdul Fazi"
व्याख्या :

Answer: A) Abdul Fazi Explanation: In 1574 Akbar started a Maktab Khana or a house of translation works in Fatehpur Sikri. He endorsed the work to a few officials to make translations of the Sanskrit books Rajatarangini, Ramayana and Mahabharata into the Persian language. In that officials, Abdul Fazi translated Ramayana into Persian.

प्र: Which of these relationships is true of an uncharged atom? 5338 0

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    The atomic mass is equal to the atomic number.
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    The number of electrons is equal to the number of neutrons.
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    The number of protons is equal to the number of electrons.
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    The atomic mass is equal to the number of electrons.
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उत्तर : 3. "The number of protons is equal to the number of electrons."
व्याख्या :

Answer: C) The number of protons is equal to the number of electrons. Explanation: The number of protons is equal to the number of electrons. That is the number of positive charges is equal to the number of negative charges.

प्र: Lichens are the best indicator of 5313 1

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    Air pollution
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    Sound pollution
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    Noise pollution
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  • 4
    Water pollution
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उत्तर : 1. "Air pollution"
व्याख्या :

Answer: A) Air pollution Explanation: 1. Lichens are plants that grow in exposed places such as rocks or tree bark.   2.  Lichens are widely used as environmental indicators or bio-indicators. They can be used as air pollution indicators, especially of the concentration of sulfur-di-oxide in the atmosphere.     3. They need to be very good at absorbing water and nutrients to grow there.

प्र: Pen is to poet as needle is to 5295 0

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    Sewing
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    Thread
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    Tailor
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    Button
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उत्तर : 3. "Tailor"
व्याख्या :

Answer: C) Tailor Explanation: Here Pen is a tool which is used to write and poet uses it. Then, the needle is a tool which is used to stitch and it is used by Tailor. Except tailor, none of the other options is a person to use it.   Hence, Pen : Poet :: Needle : Tailor

प्र: A person takes 20 minutes more to cover a certain distance by decreasing his speed by 20%. What is the time taken to cover the distance at his original speed ? 5275 0

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    1hr
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    1 hr 20 min
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    1 hr 10 min
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  • 4
    50 min
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उत्तर : 2. "1 hr 20 min"
व्याख्या :

Answer: B) 1 hr 20 min Explanation: Let the distance and original speed be 'd' km and 'k' kmph respectively. d/0.8k - d/k = 20/60 => 5d/4k - d/k = 1/3 => (5d - 4d)/4k = 1/3 => d = 4/3 k Time taken to cover the distance at original speed = d/k = 4/3 hours = 1 hour 20 minutes.

प्र: Two persons start running simultaneously around a circular track of length 300 m from the same point at speeds of 15 km/hr and 25 km/hr. When will they meet for the first time any where on the track if they are moving in opposite directions  ? 5259 0

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    27 sec
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  • 2
    31 sec
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  • 3
    23 sec
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  • 4
    29 sec
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उत्तर : 1. "27 sec"
व्याख्या :

Answer: A) 27 sec Explanation: Time taken to meet for the first time anywhere on the track = length of the track / relative speed = 300 / (15 + 25)5/18 = 300x 18 / 40 x 5 = 27 seconds.

प्र: The average weight of 45 passengers in a bus is 52 kg. 5 of them whose average weight is 48 kg leave the bus and other 5 passengers whose average weight is 54 kg join the bus at the same stop. What is the new average weight of the bus? 5251 0

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    54.21 kgs
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    51.07 kgs
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    52.66 kgs
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    53.45 kgs
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उत्तर : 3. "52.66 kgs"
व्याख्या :

Answer: C) 52.66 kgs Explanation: Given total number of passengers in the bus = 45 First average weight of 45 passengers = 52 kgs Average weight of 5 passengers who leave bus = 48 Average weight of 5 passengers who joined the bus = 54 Therefore, the net average weight of the bus is given by = 45 x 52 - 5 x 48 + 5 x 5445 = 237045= 1583= 52.66 kgs.

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