When a beam of white light is allowed to fall on a prism, the maximum deviation of the emerging light occurs for
- A.red light
- B.violet light
- C.yellow light
- D.blue light
Correct answer
Explanation
The correct answer is B, violet light. Violet has the shortest wavelength in visible light, so glass slows it the most and bends it the most. White light is a mix of seven colours, remembered as VIBGYOR. The refractive index of glass is slightly different for each colour, highest for violet and lowest for red. So when white light passes through a prism, each colour bends through a different angle and the light spreads into a coloured band called a spectrum. This splitting is called dispersion, and Isaac Newton showed it with a glass prism in his experiments of 1666. A rainbow is the same dispersion happening inside raindrops. Option A is wrong because red has the longest wavelength and is bent the least, so it lies at the other end of the spectrum from violet. Option C is wrong because yellow lies in the middle of the spectrum and deviates less than violet. Option D is wrong because blue bends more than yellow but still a little less than violet. Exam tip: red deviates least and violet most; the shorter the wavelength, the bigger the bend.
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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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
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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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.
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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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.
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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