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General ScienceHardAsked in: RRB ALP · 14 Aug 2018, Shift 1

If the kinetic energy of a body becomes 256 times its initial value, then the new linear momentum will be:

  1. A.The same as the initial value
  2. B.8 times the initial value
  3. C.16 times the initial value
  4. D.32 times the initial value

Correct answer

C. 16 times the initial value

Explanation

The correct answer is C, 16 times the initial value. Kinetic energy depends on the square of the momentum, so the momentum grows as the square root of the energy. For a body of mass m, the kinetic energy can be written as p squared divided by 2m, where p is the linear momentum. If the mass does not change, p equals the square root of 2mE, so p is proportional to the square root of E. When the kinetic energy becomes 256 times, the momentum becomes the square root of 256, that is 16 times its earlier value, and the speed also becomes 16 times. Option A is wrong because a body cannot gain energy while its momentum stays the same. Option B is wrong because 8 times the momentum would make the energy 64 times, not 256 times. Option D is wrong because 32 times the momentum would make the energy 1024 times. Exam tip: E equals p squared by 2m, so if the energy becomes n times the momentum becomes root n times, and if the momentum becomes n times the energy becomes n squared times.

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Q2.General ScienceAsked in: CDS · CDS-I 2019, GKEasy

Which one of the following statements is correct?

  1. A.Urea is produced in liver.
  2. B.Urea is produced in blood.
  3. C.Urea is produced from digestion of starch.
  4. D.Urea is produced in lung and kidney.
Show answer
Correct answer: A. Urea is produced in liver.

Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.

Q3.General ScienceAsked in: CDS · CDS-I 2019, GKMedium

Which one of the following is the correct sequence of passage of light in a compound microscope?

  1. A.Condenser-Objective lens-Eyepiece-Body tube
  2. B.Objective lens-Condenser-Body tube-Eyepiece
  3. C.Condenser-Objective lens-Body tube-Eyepiece
  4. D.Eyepiece-Objective lens-Body tube-Mirror
Show answer
Correct answer: C. Condenser-Objective lens-Body tube-Eyepiece

Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.

Q4.General ScienceAsked in: CDS · CDS-I 2019, GKEasy

Which one of the following statements regarding haemoglobin is correct?

  1. A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
  2. B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
  3. C.Haemoglobin of RBC can carry only carbon dioxide.
  4. D.Haemoglobin is only used for blood clotting and not for carrying gases.
Show answer
Correct answer: B. Haemoglobin of RBC can carry both oxygen and carbon dioxide.

It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.

Q5.General ScienceAsked in: CDS · CDS-I 2019, GKEasy

Which one of the following statements regarding histone proteins is correct?

  1. A.Histones are proteins that are present in mitochondrial membrane.
  2. B.Histones are proteins that are present in nucleus in association with DNA.
  3. C.Histones are proteins associated with lipids in the cytosol.
  4. D.Histones are proteins associated with carbohydrates in the cytosol.
Show answer
Correct answer: B. Histones are proteins that are present in nucleus in association with DNA.

They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.