IIT JEE Practice Question and Answer

Q: The average salinity of seawater is 1054 0

  • 1
    35%
    Correct
    Wrong
  • 2
    3.5%
    Correct
    Wrong
  • 3
    3%
    Correct
    Wrong
  • 4
    2.5%
    Correct
    Wrong
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Answer : 2. "3.5%"
Explanation :

Answer: B) 3.5% Explanation: Seawater or salt water is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of approximately 3.5% or 35 parts per thousand. This means that for every 1 litre (1000 mL) of seawater there are 35 grams of salts dissolved in it.   Hence, The average salinity of seawater is 3.5%.

Q: Two parallel chords on the same side of the centre of a circle are 5 cm apart. If the chords are 20 and 28 cm long, what is the radius of the circle? 1054 0

  • 1
    14.69 cm
    Correct
    Wrong
  • 2
    15.69 cm
    Correct
    Wrong
  • 3
    18.65 cm
    Correct
    Wrong
  • 4
    16.42 cm
    Correct
    Wrong
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Answer : 2. "15.69 cm"
Explanation :

Answer: B) 15.69 cm Explanation: Draw the two chords as shown in the figure. Let O be the center of the circle. Draw OC perpendicular to both chords. That divides the two chords in half.So CD = 10 and AB = 14. Draw radii OA and OD, both equal to radius r.We are given that BC = 5, the distance between the two chords. LetOB = x. We use the Pythagorean theorem on right triangle ABO AO² = AB² + OB² r² = 14² + x² We use the Pythagorean theorem on right triangle DCO DO² = CD² + OC² We see that OC = OB+BC = x+5, so r² = 10² + (x+5)² So we have a system of two equations: r² = 14² + x² r² = 10² + (x+5)² Since both left sides equal r², set the right sidesequal to each other. 14² + x² = 10² + (x+5)² 196 + x² = 100 + x² + 10x + 25 196 = 125 + 10x 71 = 10x 7.1 = x r² = 14² + x² r² = 196 + (7.1)² r² = 196 + 50.41 r² = 246.41 r = √246.41 r = 15.69745202 cm

Q: 3/4 divided by 2 is 1053 0

  • 1
    3/2
    Correct
    Wrong
  • 2
    2/3
    Correct
    Wrong
  • 3
    8/3
    Correct
    Wrong
  • 4
    3/8
    Correct
    Wrong
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Answer : 4. "3/8"
Explanation :

Answer: D) 3/8 Explanation: 3/4 divided by 2 = 3/4/2 = 3/4x2 = 3/8.   Hence, 3/4 divided by 2 is equal to 3/8.

Q: First woman to win olympic medal for India 1053 0

  • 1
    Mary Kom
    Correct
    Wrong
  • 2
    Saina Nehwal
    Correct
    Wrong
  • 3
    Karnam Malleshwari
    Correct
    Wrong
  • 4
    P.V. Sindhu
    Correct
    Wrong
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Answer : 3. "Karnam Malleshwari"
Explanation :

Answer: C) Karnam Malleshwari Explanation: The first Indian woman to ever win an Olympic medal for India was Karnam Malleswari who won a bronze medal at the Sydney Olympics 2000 in the Women's 69 kg category in Weightlifting.   Karnam Malleswari is a retired Indian weightlifter. In 1995 she received the Rajiv Gandhi Khel Ratna, India's highest sporting honour, and in 1999 the civilian Padma Shri award.   After that Indian women who won Olymic medals to India was :    1. Mary Kom at the London 2012 Summer Olympics won bronze medal in women's boxing.   2. Saina Nehwal was the first Indian to win a medal in Badminton at the Olympics, by winning the Bronze medal at the London Olympics 2012.   3. Sakshi Malik became the first Indian woman to win a medal in Wrestling. She won the Bronze medal in Women's 58 kg freestyle wrestling in 2016 Summer Olympics held in Rio.   4. P.V. Sindhu became the first ever Indian woman to win the Silver medal at the Olympics, by reaching the Badminton final at Rio Olympics 2016.

Q: What is the difference between the number of uneducated females in city P and that of uneducated males in city S ? 1052 0

  • 1
    9 lakhs
    Correct
    Wrong
  • 2
    6 lakhs
    Correct
    Wrong
  • 3
    3 lakhs
    Correct
    Wrong
  • 4
    2 lakhs
    Correct
    Wrong
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Answer : 1. "9 lakhs"
Explanation :

Answer: A) 9 lakhs Explanation: Educated females in city P = 25 lakhs Uneducated females in city P = 30 - 25 = 5 lakhs Educated males city S = 21 lakhs Educated males in city S = 35 - 21= 14 lakhs Required difference = 14 - 5 = 9 lakhs

Q: Why is burning coal a major source of pollution? 1052 0

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Answer :
Explanation :

Coal is chemically complex fuel. Whenever it is burned, gases are given off and particles of ash, called "fly ash," are released. Release of sulfur from burning into the air. The sulfur in coal combines with oxygen to form sulfur dioxide, which can be a major source of air pollution if emitted in large enough quantities. This stuff comes back as acid rain when it attaches itself to a raindrop.    Today, many of the effects of coal burning have been reduced significantly or eliminated. This is super-nasty and is only stopped by buying low-sulfur coal from Montana or Wyoming. The eastern power plants have to pay to move the coal from out west and this increases the price of power production.

Q: Order of basicity of amines in gaseous state? 1051 0

  • 1
    2'> 1'> 3' > NH3
    Correct
    Wrong
  • 2
    3' > 2' > 1'> NH3
    Correct
    Wrong
  • 3
    1' > 2' > 3'> NH3
    Correct
    Wrong
  • 4
    2'> 3'> 1' > NH3
    Correct
    Wrong
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Answer : 2. "3' > 2' > 1'> NH3"
Explanation :

Answer: B) 3' > 2' > 1'> NH3 Explanation: The order of basicity in ammonia is different in gaseous phases vs. aqueous phases due to hydrogen bonding.   So in gaseous phases it's the well known: 3' > 2' > 1'> NH3. Just so we're on the same page, this is due to the inductive effect of electron donating alkyl groups--they destabilize the lone pair on nitrogen atom, making nitrogen more basic.   But in aqueous phase, the order is slightly different: 2'> 1'> 3' > NH3.

Q: Air pressure is measured in which of the following units? 1051 0

  • 1
    Steridian
    Correct
    Wrong
  • 2
    kg/mts
    Correct
    Wrong
  • 3
    Newton
    Correct
    Wrong
  • 4
    Pascal
    Correct
    Wrong
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Answer : 4. "Pascal"
Explanation :

Answer: D) Pascal Explanation: Pressure = (Net Force) / (Applied area) = Newton / square meters Measuring units of pressure are: . Pascal. Bar. Torr. Pounds per square inch (psi). Standard atmosphere (atm).

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