Electricity Worksheet-16
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Why is tungsten used almost exclusively for filament of incandescent lamps ?
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Why are the conductors of electric heating devices, such as toasters and electric irons, made of an alloy rather than a pure metal ?
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Why is the series arrangement not used for domestic circuits ?
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How does the resistance of a wire vary with its cross-sectional area ?
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Why are copper and aluminium wires usually employed for electricity transmission.
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What is meant by quantization of charge ?
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What is an electric current ? Give its SI unit.
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What is represented by joule/coulomb ?
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A charge of 2 C moves between two plates, maintained at a potential difference of 1V. What is the energy acquired by the charge ?
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Why are copper wires used as connecting wires?
Answer:
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Tungsten has a high melting point (3380°C) and it becomes incandescent or it emits light at a high temperature at around 2400 K.
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The resistivity of an alloy is generally higher than that of pure metals of which it is made of.
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In series arrangement, in case any one of the appliances fails or is switched off, all the other appliances stop working because the same current is passing through all the appliances.
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The resistance of a wire (R) varies inversely as its cross-sectional area (A) as R ∝ 1/A.
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Copper and Aluminium wires possess low resistivity and as such are generally used for electricity transmission.
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A charged body has only integral multiples of electronic charge on it, i.e.,
Q = ne where n = ± 1, ± 2, …
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The ordered flow of electric charges through a conductor is called electric current and it is equal to charge flowing per unit time, current = charge/time. Its SI unit is an ampere (A).
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It is SI unit of potential difference, i.e., volt.
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Energy acquired, W = QV = 2C × 1V = 2 J.
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The electrical resistivity of copper is low.
