CBSE Class 10 Science 2019 · Paper 31/2/3 · Question 1
Why does the cord of an electric oven not glow while its heating element does ?
Answer
The cord has very small resistance but the element has large resistance, so by the element becomes hot and glows.
The cord and the heating element are in series, so the same current flows through both. The cord is made of copper, whose resistance is very small, while the heating element is made of an alloy such as nichrome, whose resistance is large. Since the heat produced is , almost all the heat is produced in the element, which becomes red hot and glows, while the cord stays cool.
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