The difference of temperature in a material can convert heat energy into electrical energy. To harvest the heat energy, the material should have
- (A)low thermal conductivity and low electrical conductivity
- (B)high thermal conductivity and high electrical conductivity
- (C)low thermal conductivity and high electrical conductivity✓ Correct
- (D)high thermal conductivity and low electrical conductivity
Answer: (C)
Solution
Converting a temperature difference into electrical energy relies on the Seebeck effect. To make this conversion efficient, the material must sustain a large temperature difference across its length while still allowing the induced charge carriers to flow easily.
A low thermal conductivity resists heat flow between the hot and cold ends, so the temperature gradient across the material persists instead of equalizing quickly. A high electrical conductivity lets the charge carriers generated by this gradient move with little resistive loss, so the electrical output is not wasted as heat inside the material itself.
The ideal thermoelectric material therefore combines low thermal conductivity with high electrical conductivity.
A low thermal conductivity resists heat flow between the hot and cold ends, so the temperature gradient across the material persists instead of equalizing quickly. A high electrical conductivity lets the charge carriers generated by this gradient move with little resistive loss, so the electrical output is not wasted as heat inside the material itself.
The ideal thermoelectric material therefore combines low thermal conductivity with high electrical conductivity.
JEE Main · 2025 · 29 Jan 2025 · Shift 2 · Single correct option