Surface of some metals loses their brightness when kept in air for a long time. Why?
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Elements with valency 1 are (a) always metals (b) always metalloids (c) either metals or non-metals (d) always non-metals
(c) either metals or non-metals
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Which of the following statements is correct? a. All metals are ductile. b. All non-metals are ductile. c. Generally, metals are ductile.
(c) Generally, metals are ductile. However, mercury metal - a liquid at room temperature - cannot be drawn into wires and is not ductile.
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Choose the correct alternative: (a) Alloys of metals usually have (greater/less) resistivity than that of their constituent metals.
(a) Alloys of metals usually have greater resistivity than that of their constituent metals. (b) Alloys usually have lower temperature coefficients of resistance than pure metals. (c) The resistivity of the alloy,...
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The one parameter that determines the brightness of a light source sensed by an eye is
(d) total luminous flux entering the eye.
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The brightness producing capacity of a source (a) does not depend on its power (b) does not depend on the wavelength emitted
(c) depends on its power (d) depends on the wavelength emitted.
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A 5.0 cm long straight piece of thread is kept on the surface of water. Find the force with which the surface on one side of the thread pulls it.
Length of the thread, L = 5.0 cm =0.05 m The surface tension of the water, S = 0.076 N/m Hence the force of surface tension on one side of the thread...
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A 5.0 cm long straight piece of thread is kept on the surface of water. Find the force with which the surface on one side of the thread pulls it.
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A piece of charcoal and a piece of shining steel of the same area are kept for a long time in an open lawn in bright sun.
The correct answer is (c) (d) (c) If both are picked up by bare hands, the steel will be felt hotter than the charcoal. (d) If the two are picked up from...
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Consider the following statements: l. Albedo of an object determines its visual brightness when viewed with reflected light.
(a) Albedo is the fraction of the incident sunlight that is reflected. When an object reflects most of the light that hits it and looks bright then it has high...
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A piece of iron of mass 100g is kept inside a furnace for a long time
mass of Iron = 100g water Eq of caloriemeter = 10g mass of water = 240g Let the Temp. of surface = 0ºC Siron = 470J/kg°C Total heat gained = Total heat lost. So,100/1000× 470 ×...
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