if a candle was sorounded by magnifying glasses then sealed in a box of inward facing mirrors, wt happenes?

Answer 1

The candle would burn out without oxygen.

Answer 2

I assume when asking you intended a continuing supply of air and exhaust of fumes.
You appear to be aiming to ask what would happen if all radiated heat was returned to the candle.

IMHO the lenses would not even be necessary to the arrangement. A curved mirror behaves in many ways the same as a lense.
The wax would melt much faster.
If the reflected heat was reflected sufficiently precisely on the wick, it might be kept hot enough to vaporise the molten wax equally fast, in which case the candle would burn faster.
Probably more likely, the wax would melt so fast that it drowned the wick and put the flame out, or if very diffusely focussed, the whole candle might soften and collapse.

I bow in deference to "pub bore"'s answer which has just appeared.

Answer 3

Are you trying to keep all of the flame's heat inside the flame, i.e., to complete the combustion of the wax before you let any of the heat get out? This would be the closest you'd get to anything vaguely spectacular. But if so, you can't seal the box because the flame will go out (no oxygen). So let's assume you're going to let air in and the combustion gases out, but you're just preventing heat transfer from within the flame itself.

So if you did that, the combustion gases would reach the "adiabatic flame temperature" which is basically the temperature the gases would get to if you started with the raw gases and just happened to dump an amount of heat into it that's equivalent to the chemical energy released by the burning. I once calculated it for a premixed coal flame with highly preheated air - it came out around 2200C. No real coal flame does that cos it's just a theoretical number. Your candle flame (theoretical or not) doesn't preheat the air, so I'm guessing it would come out around 1800C. The actual point of maximum temperature is difficult to work out because yours is a diffusion flame - the air is not premixed with the fuel.

Answer: a very white, bright flame, but no extra heat per se.

Answer 4

If the candle is alight it will be starved of oxygen in a sealed box and will extinguish. If it is alight and the box allows oxygen to pass in and the carbon dioxide to exit then all that will really happen is that due to convection and radiated heat transfer the candle will melt prematurely

Answer 5

The candle would go out after it burned up all the oxygen inside the box. Before ths happens it would probably be very bright inside the box.

Answer 6

The candle would be reflected, but would not re-emit any more light than the candle produces. When the candle goes out because of lack of oxygen, the light ceases also.

Answer 7

Sealed in a box, the flame would consume all remaining oxygen in the box and then die out.

Answer 8

The candle would go out, just like everyone else said

Answer 9

As soon as it was sealed it would burn out quite quickly,no oxygen.

Answer 10

Combustion requires oxygen...