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ICSE Class 10 Physics Question 16 of 20

Solved 2020 Question Paper ICSE Class 10 Physics — Question 11

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11
Question

Question 8(b)

(i) What are superconductors? [3]

(ii) Calculate the current drawn by an appliance rated 110 W, 220 V when connected across 220 V supply.

(iii) Name a substance whose resistance decreases with the increase in temperature.

Answer

(i) A superconductor is a substance of zero resistance (or infinite conductance) at a very low temperature.

(ii) For the given appliance, W = 110 W, V = 220 V

∴Current I=WV=110220=0.5 A\therefore \text{Current I} = \dfrac{W}{V} = \dfrac{110}{220} = 0.5 \text{ A}

Hence, current drawn by the appliance = 0.5 A

(iii) The resistance of semi conductors such as carbon, silicon, etc., decreases with increase in temperature.