Reflectance Equal to Transmittance

[says]

Homework Statement

Under what conditions would the reflectance, R, and the transmittance, T, be equal to each other at normal incidence at an interface? What would be the values of R and T under these conditions?

Homework Equations

R^s = |r^s|²

T^s = |t^s|² η₂cosθ_t / η₁cosθ_i

R^s + T^s = 1

r^s = η₂cosθ_i - η₁cosθ_t / η₂cosθ_i + η₁cosθ_t

t^s = 1 + r^s

t & r = Fresnel coefficients
R = Reflectance
T = Transmittance
η = refractive indicies

The Attempt at a Solution

I've been given these equations and the t^s makes me think that there are no conditions in which transmittance can be equal to each other at normal incidence at an interface.

The second part of this question, 'What would be the values of R and T under these conditions?' makes me think I'm wrong, but I don't understand how they could be equal...

 

[theodoros.mihos]

If you talk about light, see Brewster's angle definition.

 

[Simon Bridge]

Why would the t^s lead you to think there are no conditions such that R=T?
Have you tried putting R=T in the equations and checking?