A sphere G of radius b is fixed mid-air and several spheres ident

Subject

Life Sciences

Class

CNET Class 12

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Sample Papers

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 Multiple Choice QuestionsMultiple Choice Questions

1.

In a group of students, 30% play only cricket, 20% play only football and 10% play only basketball. 20% of the students play both basketball and cricket, 10% play both football and basketball. 15 students play no games, while 5% of the students play all three games. What is the total number of students?

  • 300

  • 250

  • 350

  • 400


2.

Five persons A, B, C, D, and E are sitting in a row with C in the middle of the group. If D is at an extreme end and there at least two persons between B and E, then which of the following statements is incorrect?

  • E can be on the extreme left

  • E can be on extreme right

  • A cannot be on extreme left

  • A is always a neighbour of B or D.


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3.

A sphere G of radius b is fixed mid-air and several spheres identical to the first one are shot at it with their velocities parallel to each other. If the shot spheres fall within an imaginary cylinder of radius a (b << a) then the fraction of spheres that will hit G is

  • 2b/ a

  • 4b2/a2

  • (a - b)/ (a + b)

  • 8b3/a3


B.

4b2/a2

The area of sphere = 4πr2 ( Here, r is the radius)

Let us assume there are N numbers of spheres are being shot therefore, the area of N numbers of spheres will be:

N × 4πr2 = N × 4πb2 (from question, r = b)

Now, the area of imaginary cylinder = πr2 = πa2 (r = a)

Now, 1 ball of fall into the area = πa2

Therefore, N number of ball or spheres fall into = N × πa2

Now, the fraction of spheres that will hit G would be =

N × numbers of spheresN × area of cylinder = N × 4πb2N × a2 = 4b2a2


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4.

The distance from Nehrunagar to Gandhinagar is 27 km. A and B start walking from Nehrunagar towards Gandhinagar at speeds of 5 km/hr and 7 km/hr, respectively. B reaches Gandhinagar, returns immediately, and meets A at Indiranagar. What is the distance between Nehrunagar and Indiranagar? (Assume all three cities to be in one straight line)

  • 12.5 km

  • 22.5 km

  • 4.5 km

  • 15.5 km


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5.

A leaf appears green in daylight. If this leaf were observed in red light, what colour would it appear to have?

  • green

  • black-brown

  • red

  • blue


6.

Approximately how much blood flows per day through a normal human heart beating 70 times per minute, having a relaxed volume of 110 cc and compressed volume of 70 cc?

  • 7150 litres

  • 4000 litres

  • 28000 litres

  • 11100 litres


7.

The molar function of hydrochloric acid in an extremely dilute aqueous solution is doubled. The pH of the resulting solution is

  • approximately doubled

  • approximately halved

  • increased

  • reduced


8.

The bar chart above shows the number of seats won by four political parties A, B, C, and D. Which party won the largest proportion of seats it contested?

  • A

  • B

  • C

  • D


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9.

Find the missing number.

  • 4

  • 9

  • 3

  • 6


10.

When Ramesh was at the age of 8 years, he hammered a nail into a large tree to mark his height. If the tree grows 2cm/ year, how much higher would the nail be after 5 years?

  • 5 cm higher

  • 0 cm higher

  • 10 cm higher

  • 8 cm higher


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