IIT JEE Practice Question and Answer
8Q: When is genetic drift a major factor in evolution? 4114 05b5cc67be4d2b4197774c1fa
5b5cc67be4d2b4197774c1fa- 1When there is male competitionfalse
- 2When there is artificial selectionfalse
- 3When there is no selective pressuretrue
- 4When there is disruptiveselectionfalse
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Answer : 3. "When there is no selective pressure"
Explanation :
Answer: C) When there is no selective pressure Explanation: Genetic drift or allelic drift is the change in the relative frequency in which a gene variant (allele) occurs in a population due to random sampling and chance. When is genetic drift a major factor in evolution is * When there is low gene flow. * When there is no selective pressure. * When there is a bottleneck.
Q: Find the least number by which 175760 be divided to make it a perfect cube. 4113 05b5cc6d7e4d2b4197774e70f
5b5cc6d7e4d2b4197774e70f- 16false
- 210true
- 39false
- 430false
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Answer : 2. "10"
Explanation :
Answer: B) 10 Explanation: 175760 =2³ x 2 x 5 x 13³= 2³ x 2 x 5 x 13³ To make perfect cube, it must be divided by 2 x 5 = 10
Q: A Certain sum of money an amounts to Rs 2500 in a span Of 5 years and further to Rs.3000 in a span of 7 years at simple interest The sum is ? 4110 05b5cc73de4d2b4197774f972
5b5cc73de4d2b4197774f972- 1Rs. 1800false
- 2Rs. 2000false
- 3Rs. 1400false
- 4Rs. 1250true
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Answer : 4. "Rs. 1250"
Explanation :
Answer: D) Rs. 1250 Explanation: 2500 in 5th year and 3000 in 7th year So in between 2 years Rs. 500 is increased => for a year 500/2 = 250So, per year it is increasing Rs.250 then in 5 years => 250 x 5 = 1250Hence, the initial amount must be 2500 - 1250 = Rs. 1250
Q: In a row of boys, Haran is eleventh from the left and manoj is seventeenth form the right. When they exchange their places than Haran will be thirteenth from the left. Which of the following will be the new position of Manoj from the right ? 4054 05b5cc6c6e4d2b4197774de4f
5b5cc6c6e4d2b4197774de4f- 111false
- 219true
- 313false
- 417false
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Answer : 2. "19"
Explanation :
Answer: B) 19 Explanation: Here total number of boys in the row = 11 + 19 = 13 + 17 = 30 Here after exchanging the places of Haran & Manoj => Manoj replaces Harans place of 11th from left But in the question he asked Manoj's place from right = 30 - 11 = 19th place.
Q: In an exam, a candidate secured 504 marks out of the maximum mark of 'M'. If the maximum mark 'M' is converted into 800 marks, he would have secured 384 marks. What is the value of 'M' ? 4054 05b5cc6ebe4d2b4197774ee9b
5b5cc6ebe4d2b4197774ee9b- 1910false
- 21000false
- 3970false
- 4None of the abovetrue
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Answer : 4. "None of the above"
Explanation :
Answer: D) None of the above Explanation: 504/M = 384/800 (504 x 800) / 384 = M M = 1050
Q: A compass always points to 4053 25b5cc60ae4d2b4197774b572
5b5cc60ae4d2b4197774b572- 1Northfalse
- 2Magnetic northtrue
- 3Magnetic Southfalse
- 4Southfalse
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Answer : 2. "Magnetic north"
Explanation :
Answer: B) Magnetic north Explanation: Wherever on earth we hold a compass, the needle points towards the magnetic North Pole. A compass is a great tool for navigation. Compass is widely used in aircrafts, ships, military services,...
Q: Which of the following is not an allotrope of carbon? 4047 05b5cc683e4d2b4197774c292
5b5cc683e4d2b4197774c292- 1Diamondfalse
- 2Graphenefalse
- 3Ethylenetrue
- 4Buckminsterfullerenefalse
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Answer : 3. "Ethylene"
Explanation :
Answer: C) Ethylene Explanation: Allotropes are different structural modifications of an element, that is, each of two or more different physical forms in which an element can exist. Carbon is capable of forming many allotropes due to its valency. Well-known forms of carbon include charcoal, diamond, graphite, buckminsterfullerene and graphene. Hence, Ethylene is not an allotrope of Carbon.
Q: The average number of visitors of a library in the first 4 days of a week was 58. The average for the 2nd, 3rd, 4th and 5th days was 60.If the number of visitors on the 1st and 5th days were in the ratio 8 : 9. Then what is the number of visitors on the 5th day of the library ? 4045 05b5cc74ae4d2b4197774fac7
5b5cc74ae4d2b4197774fac7- 154false
- 264false
- 368false
- 472true
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Answer : 4. "72"
Explanation :
Answer: D) 72 Explanation: If number of visitors on 1st, 2nd, 3rd, 4th & 5th day are k, l, m, n & o respectively, thenk + l + m + n = 58 x 4 = 232 ---- (i) & l + m + n + o = 60 x 4 = 240 ---- (ii)Subtracting (i) from (ii), we get o-k = 8 ---(iii)Given, k/o = 8/9 ----(iv)So from (iii) & (iv), we geta = 64, e = 72Therefore, number of visitors on 5th day is 72.