Which among the following are commonly used for making a safety pin?
(a) Wood and glass
(b) Plastic and glass
(c) Leather and plastic
(d) Steel and plastic
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A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror.
(b) – 20 cm is the correct option.
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Which method is commonly used for improving cattle breeds and why?
Cattle farming is commonly used for improving cattle breeds. The purpose of cattle farming is to increase the production of milk and draught labour for agricultural work. Dairy animals (females)...
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Name two safety measures commonly used in electric circuits and appliances
(i) Electric fuse (ii) Earthing of metal bodies of electrical appliances
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Which among the following factors is the most important in making fluorine the strongest oxidising agent?
(d) : The bond dissociation energy of F – F bond is very low. The weak F – F bond makes fluorine the strongest oxidising halogen.
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Which of the following element has the property of diffusing through most commonly used
This element has the property of diffusing through most commonly used laboratory materials such as rubber, glass or plastics (c) He
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Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes ? (1) Retrovirus (2) Ti plasmid
Ans (1) Retrovirus is commonly used as a vector for introducing a DNA fragment in human lymphocytes
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Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes ? (1) Retrovirus (2) Ti plasmid
1 Answers
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A fuse is used in mains electric supply as a safety device. Which one of the following statements about the fuse is correct?
(c) A fuse is a type of sacrificial overcurrent protection device. Its essential component is a metal wire or strip that melts when too much current flows. Short circuit, overload...
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Which one of the following is printed on a commonly used fluorescent tube light?
(c) A fluorescent lamp or fluorescent tube is a gasdischarge lamp that uses electricity to excite mercury vapour. The excited mercury atoms produce shortwave ultraviolet light that then causes a...
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Which one of the following pairs of materials serves as electrodes in chargeable batteries commonly used in devices such as torchlights,
(a) Ni-Cd batteries contain nickel hydroxide as positive electrode plate, a cadmium hydroxide as negative electrode plate, and an alkaline electrolyte as seperator. The chemical reaction which occurs in Ni-Cd...
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