Bronze is an alloy of
- A.Cu and Zn
- B.Cu and Sn
- C.Zn and Mg
- D.Fe and Cu
Correct answer
Explanation
The correct answer is B, Cu and Sn. Bronze is made by mixing copper (Cu) with tin (Sn), usually about nine parts copper to one part tin. Adding tin makes the metal harder, stronger and more resistant to corrosion than pure copper, which is why bronze was used for tools, weapons, bells, coins and statues. It was so important in early history that a whole period, the Bronze Age, is named after it; the Harappan dancing girl and the Chola Nataraja images are famous bronze works. Option A is wrong because copper and zinc together make brass, the yellow alloy used in utensils, fittings and musical instruments. Option C is wrong because zinc and magnesium do not form any common alloy known by this name; magnesium is usually alloyed with aluminium in light alloys such as magnalium. Option D is wrong because iron and copper are not the basis of bronze; iron is the main metal of steel, which is iron with a little carbon. Exam tip: bronze = copper + tin; brass = copper + zinc; German silver = copper + zinc + nickel.
Practice Questions
View allChlorophyll in photosynthetic prokaryotic bacteria is associated with
- A.plastids
- B.membranous vesicles
- C.nucleoids
- D.chromosomes
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Photosynthetic bacteria have no chloroplasts; their pigments sit on infoldings of the cell membrane that form vesicles or sacs, often called chromatophores.
Read the full explanation →Fat in human body is stored in
- A.Adipose tissue
- B.Red blood cells
- C.Muscle tissue
- D.Epithelial tissue
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Adipose tissue is a loose connective tissue whose cells, called adipocytes, are built to store fat. Each cell holds a large droplet of fat that pushes the nucleus and cytoplasm to one side.
Read the full explanation →Which one of the following is a metalloid ?
- A.Germanium
- B.Coke
- C.Iodine
- D.Sugar
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Germanium is a metalloid, an element whose properties lie between those of metals and non-metals. It is a hard, shiny, grey-white solid like a metal, yet it is brittle and conducts electricity far less well than a metal, which makes it a semiconductor.
Read the full explanation →A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?
- A.The wavelength of X-ray photon is less than the wavelength of visible radiation photon.
- B.Both the photons have different energies.
- C.The speeds of both the photons in vacuum are different.
- D.The frequency of X-ray photon is higher than the frequency of visible radiation photon.
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This statement is wrong because every photon, whatever its energy, travels in vacuum at the same speed of light, about 3 × 10^8 metres per second.
Read the full explanation →Which of the following substances cause temporary hardness in water?
1. Mg(HCO3)2
2. Ca(HCO3)2
3. CaCl2
4. MgSO4
Select the correct answer using the code given below.
- A.3 and 4
- B.2 and 3
- C.1 and 4
- D.1 and 2
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Temporary hardness is caused by the bicarbonates of magnesium and calcium, Mg(HCO3)2 and Ca(HCO3)2. It is called temporary because simple boiling removes it: on heating, the soluble bicarbonates break down into insoluble carbonate or hydroxide, carbon dioxide and water, and the solid settles out.
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