alleryStart learning →A white shawl keeps a baby warm mainly because a white surface is a:
- poor conductor of heat
- poor radiator of heat
- good reflector of heat
- good absorber of heat
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Correct answer: B. poor radiator of heat
1. The baby loses body heat, and the shawl's job is to slow that loss.
2. Heat leaves a warm body partly by radiation from its surface.
3. White and shiny surfaces are poor radiators, so they emit heat slowly.
4. Wrapping the baby in white therefore reduces the rate at which body heat radiates away.
5. Being a good reflector matters for heat arriving from outside, not for heat leaving from within, which is why that answer misses the direction of the transfer.
_Source: NECTA CSEE 2021 Physics 031, Question 1: Multiple Choice, item (vii)_