The temperature of a substance increases by 27°C. On the Kelvin scale this increase is -
- A.2.46 K
- B.7 K
- C.27 K
- D.300 K
Correct answer
Explanation
The correct answer is C, 27 K. A rise of 27°C is a rise of 27 K, because one degree Celsius and one kelvin are exactly the same size. The two scales differ only in where they begin: the melting point of ice is 0°C but 273.15 K. So the formula T(K) = t(°C) + 273.15 converts a reading, not a difference. When two temperatures are subtracted the 273.15 cancels out, which is why a rise, a fall or an interval carries the same number on both scales. Option D, 300 K, is the trap in this question: 27 + 273 is the Kelvin reading of a body that is at 27°C, not the size of a 27-degree rise. Options A and B follow from no step at all; they would need a scale whose divisions are smaller than the Celsius degree, and the kelvin is not such a unit. Exam tip: add 273.15 to a reading, but copy an interval straight across.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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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.
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