light bulb A is half as bright as light bulb B. If light bulb A has a current of 10 amps running through it what is the current in light bulb B?

Answer 1

Joy above did a great job of explaining based on the idea that brightness means intensity. I totally agree with Joy, also, that increased current means increased brightness,

However, I believe that the amount of power applied to the bulb is linear as related to current, assuming that potential difference (voltage) is kept constant.

The equation P=VI relates them.

That would make the brightness/intensity half the amount when half of the current is provided.

Answer 2

Intensity goes as current² , doesn't it? So if the intensity_A = (1/2)intensity_B, then current_A =(1/sqrt(2))current_B .

So current_A = 10 = (1/sqrt(2)) current_B means current_B = 10*sqrt(2)

I think that's right! But I haven't thought about intensity (brightness) in a long time, so let me know! :)