The reason for the hardness of diamond is from Life Sciences Ye

Subject

Life Sciences

Class

CNET Class 12

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Sample Papers

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 Multiple Choice QuestionsMultiple Choice Questions

1.

The cumulative profits of a company since its inception are shown in the diagram. If the net worth of the company at the end of 4th year is 99 Crores, the principal it had started with was:

                                 

  • 9.0crores

  • 99 crores

  • 90 crores

  • 9.9 crores


2.

Popular use of which of the following fertilizers increase the acidity of soil?

  • Potassium nitrate

  • Ammonium sulphate

  • Urea

  • Superphoshate of lime


3.

Exposing an organism to a certain chemical can change nucleotide bases in a gene, causing mutation. In one such mutated organism if a protein had only 70% of the primary amino acid sequence, which of the following is likely?

  • Mutation broke the protein

  • The organism could not make amino acid

  • Mutation created a terminator codon

  • The gene was not transcribed


4.

The speed of a car increases very minute as shown in the following table. The speed at the end of the 19th minute would be
Times (minutes) Speed(m/sec)
1 1.5
2 3.0
3 4.5
- -
- -
24 36.0
25 37.5

  

  • 26.5

  • 28.0

  • 27.0

  • 28.5


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5.

If the atmospheric concentration of carbon dioxide is doubled and there are favourable conditions of water, nutrients, light and temperature, what would happen to water requirement of plants?

  • It decrease initially for short time and then return to original value

  • It increases

  • It decreases

  • It increases initally for short time and then return to orginal value.


6.

How many σ bond are present in the following molecules?

                      HC≡CCH=CHCH3

  • 4

  • 10

  • 6

  • 13


7.

Diabetic patients are advised a low glycaemic index diet. The reason for this is:

  • They requires less carbohydrate than healthy individuals

  • They cannot assimilate ordinary carbohydrates

  • They need to have slow, but sustained release of glucose in their blood stream.

  • They can tolerate lower, but not higher than normal blood sugar level.


8.

Glucose molecules diffuse across a cell of diameter d in time τ. If the cell diameter I tripled, the diffusion time would

  • Increase to 9 τ

  • Decrease to τ/3

  • Increase to 3 τ

  • Decrease to τ/9


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9.

The reason for the hardness of diamond is

  • Extended covalent bonding

  • Layered structure

  • Formation of cage structure

  • Formation of tubular structure


A.

Extended covalent bonding

The heat and pressure causes the diamonds molecules to change so that they are so close together, the molecules can't move [known as covalent bonding]. The closeness of these molecules from a rigid bond, therefore making diamond hard.


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10.

Which of the following particles has the largest range in a given medium if their initial energies are the same?

  • Alpha

  • Gamma

  • Positron

  • Electron


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