Ray Model of Light (HSC SSCE Physics): Flashcards

Energy per second through each unit of surface area

watts per square metre ($\text{W m}^{-2}$)

Total energy emitted per second by the source

Intensity inversely proportional to square of distance ($I \propto \frac{1}{r^2}$)

Intensity becomes one-quarter of original value

Intensity becomes one-ninth of original value

$I_1 r_1^2 = I_2 r_2^2$

Intensity is proportional to source strength ($I \propto S$)

$A = 4\pi r^2$

Gravity, electrostatic forces, sound, X-rays, gamma rays