[DeShark]

Sorry about this but I think I've got my information wrong. In fact I'm almost sure I have. I just re-read the link to wikipedia I gave you and it says quite clearly that the difference in the energy of the incident photon and the band gap energy is converted into heat. Some of the energy of the incident photon produces electricity the rest causes heat. This is why the solar panels are so inefficient. If all of the energy were converted to electricity they'd be far more effective. However it's not. A large proportion is converted to heat.

I give in Jambutty. You're right. To generate electricity the incoming photons must have *higher* energy that the band gap energy (1.1 eV = infrared). Thus your argument is correct. It depends on the *number* of photons. This is not the luminousity of the light. Nor is it the intensity. It's the number of photons. It's difficult to say that the greater number of photons, the brighter the light. Just like it's hard to say the greater the number of coins in your pocket the more money you have.

Since the luminance/brightness is based on the eye's sensitivity to the light maybe you could just say which you think appears brighter. Your calculator's solar panel is not an adequate measure of brightness because it is not more sensitive to one wavelength of light to another, whereas your eye is.