No, the light output of a lamp is the same, you’ve just focused more of it in a particular direction. It’s the same reason flashlights have a cone shaped mirror around the bulb. If it were possible to double light output, then putting a lamp between two mirrors would make infinite light.
This reminds me of a great demonstration of how directional antennas focus radio waves in one direction: https://youtu.be/lslHtCUSfN4
That was a cool vid- I don’t know much about antennas, so that was a fascinating watch. Thanks!
A mirror and a perfectly white wall both reflect (nearly) all the light that hits them, the only difference is in which direction they reflect it. White walls will scatter the light that hits them.
The lamp in the mirror is a reflection of light from the real lamp. The real lamp is producing light. The mirror lamp is a reflection of this light. The reflection doesnt add to the amount of total light
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Yeah the mirror reflects more light than a wall. But there isn’t more total light
Let’s define “more”.
Yeah, we’re not troll sciencing light out of nowhere, but if the lamp is next to a mirror instead of a wall, the room will have more illumination, because the mirror is reflecting the light emitted by the lamp better than a wall will do.
the mirror is reflecting the light emitted by the lamp better than a wall will do.
Will it? Maybe. You are making the assumption that specular reflection is better at reflecting than diffuse reflection, but that is a false assumption. It depends on the reflectivity of the wall and the mirror. A white wall can reflect more light than a mirror.
You’re just changing the direction of that light with a mirror. Picture a light bulb vs a light bulb in a flashlight with that reflector dish behind it.
Walls also do this, but to a lesser extent. If your concern is wasting light then get a lamp with a reflective directional shade. You know, like the Pixar lamp.
Depends on the color of the wall, but likely no. A matte black wall would absorb a lot of light, a matte white wall would reflect most of the light. Other colours would fall somewhere in the middle, reflecting some wavelengths and absorbing others. The only difference with a mirror is that it reflects light in a uniform fashion, whereas a painted wall will generally scatter reflected light. But scattered light still contributes to total light output! The only scenario where a mirror behind a lamp would come close to doubling light output would be if the wall we’re comparing against is painted with Vantablack or some other ultrablack paint that absorbs 99%+ of the light from the lamp.
You can say that you’ve increased the light in your direction but it is by takimg it away from the opposite side of the lamp
How can the mirror be real if the lamp isn’t real
