General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
21. Who among the following is known to manufacture first Cyclotron?
[A] Ernest Lawrence
[B] Niels Bohr
[C] Rutherford
[D] Max Born
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Correct Answer: A [Ernest Lawrence]
22. Who among the following established that genetic code of all organisms is spelled out in three-letter words, each set of three nucleotides codes for a specific amino acid?
[A] Hargobind Khorana
[B] Barbara McClintock
[C] Theodor O. Diener
[D] Joseph L. Goldstein
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Correct Answer: A [Hargobind Khorana]
23. Which among the following is “Fool’s Gold” ?
[A] Copper Sulphate
[B] Iron Sulfide
[C] Brass
[D] Silver Bromide
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Correct Answer: B [Iron Sulfide]
24. Which among the following is the unit of the scale used for measurement of the spicy heat of a chili pepper?
[A] Smith
[B] Wright
[C] Orville
[D] Scoville
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Correct Answer: D [Scoville]
25. Which of the following states of matter has the weakest Intermolecular forces?
[A] Solids
[B] Liquids
[C] Gases
[D] It is same in solids, liquids and gases
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Correct Answer: C [Gases]
Notes:
The three states of matter varies from each other due to the following factors. (1) The different magnitudes of the interatomic and intermolecular forces. (2) The extent of random thermal motion of atoms and molecules of a substance (which depends upon temperature). The Intermolecular force is strongest in solids and weakest in gases.
26. What is the property of matter by which a body tends to regain its original configuration after the removal of deforming force known as?
[A] Plasticity
[B] Ductility
[C] Elasticity
[D] Malleability
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Correct Answer: C [Elasticity]
Notes:
The property of matter because of which a body tends to regain its original shape and size after the deforming force is removed is called its elasticity. Plasticity: It is that property of matter by virtue of which it does not regain its original shape and size after the removal of deforming force.
27. What is the body called which does not have any tendency to recover its original configuration, on the removal of deforming force?
[A] Perfectly plastic
[B] Perfectly elastic
[C] Perfectly ductile
[D] None of the above
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Correct Answer: A [Perfectly plastic]
Notes:
Perfectly plastic: If the body does not have any tendency to recover its original configuration, on the removal of deforming force, it is said to be perfectly plastic. Paraffin wax, wet clay can be the closest example of the perfectly plastic body.
28. What is the unit of Stress?
[A] N/m
[B] Kg/m
[C] Nm
[D] It has no units
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Correct Answer: A [N/m]
Notes:
If an external force F is applied on the area A of a body then, Stress is given by Force/Area Units of Stress: S.I unit: N / m C.g.s unit: dyne / cm
29. What is the dimensional formula of Stress?
[A] M 1 L-2 T-2
[B] M 1 L-1 T-1
[C] M 1 L1 T-3
[D] M 1 L-1 T-2
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Correct Answer: D [M 1 L-1 T-2]
Notes:
Stress is defined as external force per unit area on a body that tends to cause it to deform. The dimensional formula of Stress is M 1 L-1 T-2
30. What is the stress known as when there is a relative displacement between various layers of solid?
[A] Tangential
[B] Linear
[C] Lateral
[D] Longitudinal
Show Answer
Correct Answer: A [Tangential]
Notes:
When successive layers of solid move on each other i.e. when there is a relative displacement between various layers of solid, the stress produced is called as Tangential stress.
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