Ulla switches on a stove burner and waits. For minutes it looks completely unchanged, no glow at all, yet it is already emitting more and more electromagnetic radiation.
That is not a special fact about burners. Every object emits, all the time; heating only raises the amount.
A cool rock, a desk, your own skin: each is emitting right now, even though none of them glows.
Emission the eye cannot see is still emission; glowing is not the test.
The stove burner radiates more and more strongly as it heats up, long before it glows visibly.
Of two otherwise similar objects, the hotter one emits more radiation each second.
A mug of hot cocoa and a matching mug of iced water sit on one table. Which emits more radiation each second?
Both emit; every object does.
The cocoa is hotter, and the mugs are otherwise alike.
The mug of hot cocoa emits more each second. The iced mug still emits too.
Does a snowball emit electromagnetic radiation?
Every object emits, warm or cold.
A snowball does not glow, but glowing is not the test.
Yes. The snowball emits electromagnetic radiation; it emits less each second than a warmer object like your hand.
A glowing coal and a room-temperature textbook sit in a classroom. Which of them is emitting electromagnetic radiation?
Two identical kettles sit on a counter: one just boiled, one at room temperature. Which emits more radiation each second?
Viggo says: 'A cool rock in the shade is emitting electromagnetic radiation right now.' Is Viggo correct?
Which statement is correct?
A dark barn at night holds a warm horse and a cold metal gate. Which statement is correct?
A stove burner is switched on and heats steadily for two minutes before any visible glow appears. During those two minutes, what happens to the radiation it emits?