IIT JEE प्रश्न और उत्तर का अभ्यास करें

प्र: Which layer of the atmosphere contains the ozone layer? 1990 0

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    Troposphere
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    Stratosphere
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    Thermosphere
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  • 4
    Mesosphere
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उत्तर : 2. "Stratosphere"
व्याख्या :

Answer: B) Stratosphere Explanation: The ozone layer is a region of Earth's Stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere.   The Atmosphere is divided into 4 layers according to major changes in temperature. They are : 1. Troposphere, 2. Stratosphere, 3. Mesosphere  and 4. Thermosphere. The farther away from earth, the thinner the atmosphere gets.

प्र: 52 C in a P? 1735 0

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उत्तर :
व्याख्या :

52 C in a P represents 52 Cards in a Pack. Similar to  12 S of the Z  5 C in an OF

प्र: Which of the following is not an intensive property? 1900 0

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    Weight
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    Density
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    Refractive index
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    Melting point
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उत्तर : 1. "Weight"
व्याख्या :

Answer: A) Weight Explanation: An intensive property is a physical quantity whose value does not depend on the amount of the substance for which it is measured. For example, the temperature of a system in thermal equilibrium is the same as the temperature of any part of it. If the system is divided the temperature of each subsystem is identical. The same applies to the density of a homogeneous system, if the system is divided in half, the mass and the volume change in the identical ratio and the density remains unchanged. Additionally, the boiling point of a substance is another example of an intensive property. For example, the boiling point for water is 100 °C at a pressure of one atmosphere, a fact which remains true regardless of quantity.

प्र: What comes next in this sequence 196, 169, 144, 121, 100, 81, ? 2244 0

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    77
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    74
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    67
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    64
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उत्तर : 4. "64"
व्याख्या :

Answer: D) 64 Explanation: The given number series follows a pattern that 196, 169, 144, 121, 100, 81, ?     -27  -25   -23   -21  -19  -17   => 81 - 17 = 64 Therefore, the series is 196, 169, 144, 121, 100, 81, 64.

प्र: A man covers half of his journey by train at 60 km/hr, half of the remaining by bus at 30 km/hr and the rest by cycle at 10 km/hr. Find his average speed during the entire journey? 1778 0

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    32 kmph
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    20 kmph
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    18 kmph
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    24 kmph
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उत्तर : 4. "24 kmph"
व्याख्या :

Answer: D) 24 kmph Explanation: Let the total distance of the journey of a man = d kms Now, the average speed of the entire journey = dd120 + d120 + d40  = 24 kmph.

प्र: At what temperature do pathogenic bacteria grow best in food? 1408 0

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    5 to 15 degrees Celsius
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    15 to 25 degrees Celsius
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    20 to 45 degrees Celsius
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    40 to 65 degrees Celsius
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उत्तर : 3. "20 to 45 degrees Celsius"
व्याख्या :

Answer: C) 20 to 45 degrees Celsius Explanation: The Bacteria that causes Food Borne illness are called Food Borne Pathogens. Most of the pathogens are mesophilic in nature, optimum temperature may be around 20-45 degree celsius. This range of temperatures is often called the "Danger Zone." Dry foods do not support the growth of bacteria.   In order to kill pathogenic bacteria you need temperatures above 74ºC. Temperature is the easiest factor to control in order to prevent bacterial growth.

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उत्तर : 3. "36"
व्याख्या :

Answer: C) 36 Explanation: Given 4men, 12 women and 20 children work for  2 days. Workdone for 2 days by 4men, 12 women and 20 children = 4 x 26 x 12 + 12 x 28 x 18 + 20 x 218 x 10 = 12 Therefore, remaining work = 1 - 12 = 12 To complete the same work by only men in 1 day, We know that M1 x D1 = M2 x D2 Here M1 = 6 , D1 = 12 and M2 = M , D2 = 1 12 x 6 = M x 1 => M = 12 x 6 = 72 => But the remaining work = 1/2 Men required => 1/2 x 72 = 36 Only men required to Complete the remaining work in 1 day = 36.

प्र: Which of the following is Not a Greenhouse Gas? 1439 0

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    Oxygen
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    Methane
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    Nitrous Oxide
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    Carbondioxide
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उत्तर : 1. "Oxygen"
व्याख्या :

Answer: A) Oxygen Explanation: A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.    Carbon dioxide is a main greenhouse gas, found in car exhaust pipes.Methane and nitrous oxide is another type of greenhouse gas. Oxygen is the only clean gas out there because we need it to survive. Therefore, the only gas that is not a greenhouse gas is Oxygen.

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