IIT JEE Practice Question and Answer

Q: Who has won the Nobel prize in "Physics" for the year 2017 ? 957 0

  • 1
    Barry Barish
    Correct
    Wrong
  • 2
    Kip Thorne
    Correct
    Wrong
  • 3
    Rainer Weiss
    Correct
    Wrong
  • 4
    All of the above
    Correct
    Wrong
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Answer : 4. "All of the above"
Explanation :

Answer: D) All of the above Explanation: Rainer Weiss, a professor at the Massachusetts Institute of Technology, and Kip Thorne and Barry Barish, both of the California Institute of Technology, were awarded the Nobel Prize in Physics for the discovery of ripples in space-time known as gravitational waves, which were predicted by Albert Einstein a century ago but had never been directly seen.

Q: A town having teenagers(boys & girls) of 5000 requires 150 litre of water per head. It has a tank measuring 20 m × 15 m × 5 m. The water of this tank will sufficient for ____ days. 956 0

  • 1
    8
    Correct
    Wrong
  • 2
    6
    Correct
    Wrong
  • 3
    4
    Correct
    Wrong
  • 4
    2
    Correct
    Wrong
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Answer : 4. "2"
Explanation :

Answer: D) 2 Explanation: Total Water reqduired = 5000 × 150 lit = 750,000 litres = 750 cu.m.   Volume of tank = 20 × 15 × 5 = 1500 Cu.m.   Number of days required =1500/750 = 2 days.

Q: A man can row 8 kmh in still water. If the river is running at 2 kmh, it takes 4 hrs more upstream than to go downstream for the same distance. Then the distance is given by 956 0

  • 1
    54 kms
    Correct
    Wrong
  • 2
    32 kms
    Correct
    Wrong
  • 3
    45 kms
    Correct
    Wrong
  • 4
    60 kms
    Correct
    Wrong
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Answer : 4. "60 kms"
Explanation :

Answer: D) 60 kms Explanation: Let the distance be d.  d8-2-d8+2 = 4   => 2d = 120    => d = 60 kms.

Q: Find the lowest 4-digit number which when divided by 3, 4 or 5 leaves a remainder of 2 in each case ? 956 0

  • 1
    1020
    Correct
    Wrong
  • 2
    1040
    Correct
    Wrong
  • 3
    1060
    Correct
    Wrong
  • 4
    1022
    Correct
    Wrong
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Answer : 4. "1022"
Explanation :

Answer: D) 1022 Explanation: Lowest 4-digit number is 1000.LCM of 3, 4 and 5 is 60.Dividing 1000 by 60, we get the remainder 40. Thus, the lowest 4-digit number that exactly divisible by 3, 4 and 5 is 1000 + (60 - 40) = 1020.Now, add the remainder 2 that's required. Thus, the answer is 1022.

Q: Brightness of bulb depends on voltage or current? 956 0

  • 1
    Current
    Correct
    Wrong
  • 2
    Voltage
    Correct
    Wrong
  • 3
    Both A & B
    Correct
    Wrong
  • 4
    None
    Correct
    Wrong
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Answer : 3. "Both A & B"
Explanation :

Answer: C) Both A & B Explanation: Brightness of bulb depends on both voltage and current. The brightness depends on power. Since we know that  Power (P) = Voltage x Current = V I So whether you increase the current or the voltage the brightness will increase.   Example Illustration:  If you connect a long bulb and a round bulb in series, the long bulb glows but the round bulb does not. Both of them have the same current flowing through them (they are in series) but the long bulb has a greater voltage across it because it has more resistance (even though V= IR is not obeyed exactly, voltage drop does depend on the resistance). If you connect a round bulb and a long bulb in parallel, however, it is the round bulb that is brighter because now the voltage across both bulbs is the same but the current is larger through the round bulb (smaller resistance).   Hence, the brightness of a bulb depends on power i.e, both voltage and current.

Q: Multiplicative inverse of 7? 955 0

  • 1
    1
    Correct
    Wrong
  • 2
    -1/7
    Correct
    Wrong
  • 3
    0
    Correct
    Wrong
  • 4
    1/7
    Correct
    Wrong
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Answer : 4. "1/7"
Explanation :

Answer: D) 1/7 Explanation: Multiplicative inverse is nothing but a reciprocal of a number.  It is defined as one of a pair of numbers that when multiplied with another number equals the number 1. Multiplicative inverse or reciprocal of 7 is  7 x n = 1 => n = 1/7.   Hence, Multiplicative inverse or reciprocal of 7 is  1/7.

Q: Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 4 or 15 ? 955 0

  • 1
    6/19
    Correct
    Wrong
  • 2
    3/10
    Correct
    Wrong
  • 3
    7/10
    Correct
    Wrong
  • 4
    6/17
    Correct
    Wrong
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Answer : 2. "3/10"
Explanation :

Answer: B) 3/10 Explanation: Here, S = {1, 2, 3, 4, ...., 19, 20}=> n(s) = 20Let E = event of getting a multiple of 4 or 15 =multiples od 4 are {4, 8, 12, 16, 20}And multiples of 15 means multiples of 3 and 5= {3, 6 , 9, 12, 15, 18, 5, 10, 15, 20}.= the common multiple is only (15).=> E = n(E)= 6Required Probability = P(E) = n(E)/n(S) = 6/20 = 3/10.

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Answer :
Explanation :

Given total number of boys in the school = 1500 In that 35% are Hindu, 30% are Sikh, 15% are Muslims => 35 + 30 + 15 = 80% Remaining Boys = 100% - 80% = 20% of 1500 => 20 x 1500/100 = 300 boys are Christians.

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