Highly polished silvery surfaces are

Step 1: Analyze the question The question asks how a highly polished, shiny (silvery) surface behaves with thermal radiation, both in absorbing it and in emitting it.

Step 2: The concept

• Dull, black surfaces are good absorbers and good emitters of radiant heat.
• Shiny, polished, light-coloured surfaces are poor absorbers and poor emitters. They reflect most of the radiation that falls on them.
• A good absorber is always a good emitter, and a poor absorber is always a poor emitter (Kirchhoff's law of radiation). So the two properties go together, and options B and C cannot be right.

Step 3: Apply it A polished silvery surface reflects most incident radiation, so it absorbs little. By the same principle, it also emits little when hot.

• B: poor absorber but good emitter. This contradicts the principle.
• C: good absorber but poor emitter. This also contradicts it.
• D: good absorber and good emitter. This describes a dull black surface.
• A: poor absorber and poor emitter. This matches a polished silvery surface.

Step 4: Real-life example This is why the inside of a vacuum flask (thermos) is silvered. It reduces heat loss by radiation (poor emitter) and also reduces heat gain from outside (poor absorber). It is also why a shiny kettle keeps water hot longer than a dull black one.

Step 5: Answer The correct option is A: poor absorbers and poor emitters of radiation.

Tip: Remember "good absorber = good emitter, bad absorber = bad emitter". Black and dull means good at both. Shiny means poor at both. If an option mixes good and poor, you can eliminate it right away.