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Science · 2025 · 3 marks
CBSE 2025 · Region 4 · Set 1 · Q32
The electrical resistivity of three materials A, B and C at 20°C is given below: (i) Classify these materials as conductor, alloy and insulator. (ii)…
The electrical resistivity of three materials A, B and C at $\displaystyle 20$°C is given below:
| Material | Resistivity $\displaystyle (\Omega \mathrm{m})$ |
| A | $\displaystyle 10^{17}$ |
| B | $\displaystyle 44 \times 10^{-6}$ |
| C | $\displaystyle 1.62 \times 10^{-8}$ |
(i)
Classify these materials as conductor, alloy and insulator.
(ii)
Give one example of each of these materials and state one use of each material in the design of an electrical appliance say an electric stove or an electric iron.
Marking-scheme solution
(i)
A - Insulator
B - Alloy
C - Conductor
(ii)
A: Plastic - handle of an electric iron.
B: Nichrome - used as a heating element in an electric iron.
C: Copper - electric wires. /
A: Rubber- foot of the electric stove.
B: Nichrome - used as a heating element in an electric stove.
C: Copper- electric wires.
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CBSE Class 10 Science past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.