We know that the intensity of light decreases as the square of the distance from the source.
Lamp-1 is twice (2x) as far from the detector as Lamp-2 is. If they appear equal to the detector, then Lamp-1 must be (2)² = 4 times as bright as Lamp-2.
4 x 15 candelas = 60 candelas
Question #15). A). is true, but has nothing to do with particle behavior B). Diffraction is a purely wave thing, so it doesn't help. C). is true, but doesn't say anything about particle behavior D). is true, but isn't an indication of particle behavior.
Looks to me like NONE of the choices is any help to suggest particle behavior.
