Wednesday 19 October 2016

Science MCQs

1. Piezoelectricity was discovered by Pierre and Jacques Curie in 1880. They discovered that pressure on a quartz crystal causes positive and negative charges to be produced across the crystal. It was later found that an alternating electrical charge placed on a piezoelectric crystal could cause the crystal to vibrate. This is the basis of the use of quartz as Oscillator plates to control radio waves and keep time. How were these two discoverers related?

  • (A) They were sisters
  • (B) They were brother and sister
  • (C) They were brothers
  • (D) There were son and father

2. Precious minerals are called gemstones. Gemstones have been a source of delight and fascination for many thousands of years. Which one of the following is not an example of a gemstone?

  • (A) Ruby
  • (B) Emerald
  • (C) Diamond
  • (D) Calcite

3. Ideally gemstones should be hard and unaffected by the temperatures, pressures, abrasive dusts and chemicals encountered in daily life. The majority of gemstones are chemically:

  • (A) Oxides
  • (B) Sulphate
  • (C) Carbonates
  • (D) Silicates

4. Which gemstone is made up of a single element?

  • (A) Sapphire
  • (B) Diamond
  • (C) Topaz
  • (D) Emerald

5. Which diamonds are the most precious and rare?

  • (A) Colourless
  • (B) Yellow coloured
  • (C) Red coloured
  • (D) Blue coloured

6. What is the usual unit of weight measurement for gems?

  • (A) Grams
  • (B) Milligrams
  • (C) Carats
  • (D) Ounces

7. How many karats make a gram?

  • (A) 5
  • (B) 10
  • (C) 2
  • (D) 3

8. A constant mathematical relationship exists between the angle at which light strikes a mineral and angle of refraction this is called the refractive index. This physical property gives brilliance to gemstones. What is the value of refractive index for diamond?

  • (A) 1.33
  • (B) 1.55
  • (C) 2.41
  • (D) 3.14

9. Ruby and Sapphire are beautiful gemstones. Their chemical composition is aluminum oxide. Which of the following countries is famous for these gems?

  • (A) Thailand
  • (B) Sri Lanka
  • (C) Tanzania
  • (D) Zimbabwe

10. Emerald is beryl mineral. Its crystal structure is hexagonal and hardness 7.5. What is its usual color?

  • (A) Red
  • (B) Blue
  • (C) Green
  • (D) Purple

11. Name the country in Asia where best quality emeralds are mined?

  • (A) India
  • (B) Pakistan
  • (C) Sri Lanka
  • (D) Maldives

12. Opal occurs in two distinct varieties precious opal and common opal. Both varieties are cut as gemstones but only precious opal displays the rainbow iridescence so highly prized in jewelry from Roman times onwards. Where is it mined most?

  • (A) Australia
  • (B) Mexico
  • (C) Czechoslovakia
  • (D) In all the above

13. Agate and Jasper are the chameleons of the gem world, displaying a bewildering variety of subtle colors and patterns. What is their chemical composition?

  • (A) Aluminum oxide
  • (B) Silicon dioxide
  • (C) Zirconium oxide
  • (D) Chromium oxide

14. Topaz is a very hard gemstone. It's usual colors vary from golden brown to pink. What is its chemical composition?

  • (A) Aluminum silicate
  • (B) Aluminum sulphate
  • (C) Aluminum oxide
  • (D) Aluminum carbonate

15. The word Diamond is derived from the Greek word Adamas, meaning "unconquerable" given to the stone because of its supreme hardness. Diamond is made of pure carbon and has an immensely strong crystal structure. Which country is the top producer of diamonds?

  • (A) Pakistan
  • (B) Brazil
  • (C) Australia
  • (D) U.S.A.

16. The Koh-i-Noor is claimed to be the oldest large diamond. It was first presented to Mughal Emperor Badur in 1526. When was this later presented to Queen Victoria?

  • (A) 1820
  • (B) 1830
  • (C) 1840
  • (D) 1850

17. Which one of the following is a famous diamond?

  • (A) Koh-i-Noor
  • (B) Blue Hope
  • (C) Premier Diamond
  • (D) All the above

18. Plants and animals were our earliest sources of ornaments. These are called organic gems. Name some gemstones synthesized by living organisms.

  • (A) Amber
  • (B) Jet
  • (C) Pearl
  • (D) All the above

19. Which one of the following organic gems is pure calcium carbonate?

  • (A) Pearls
  • (B) Corals
  • (C) Shells
  • (D) Jets

20. Artificial gems are as popular as the original ones. These are cheaper and easily available. In appearance, they look like real but are very different in compositions. What name is given to the man-made gems?

  • (A) Imitations
  • (B) Composite stones
  • (C) Synthetics
  • (D) All the above

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