WAEC SSCE - Physics - 1998 (Objective)

The inside of a vacuum flak is usually coated with silver to reduce heat loss by

evaporation

radiation Respuesta correcta

conduction

convention

condensation

Detalles de la respuesta

The correct answer is **radiation**. Heat can be transferred through vacuum by radiation, which is the emission of electromagnetic waves from a body due to its temperature. A vacuum flask consists of two walls of glass with a vacuum in between them, and this vacuum is a poor conductor of heat, which reduces heat loss by conduction and convection. However, the inner wall of a vacuum flask can still lose heat by radiation. Hence, to reduce heat loss by radiation, the inside of a vacuum flask is usually coated with a reflective surface, typically silver, which reflects heat back into the flask, keeping the contents warmer for longer.






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