A Broad Spectrum of Light λ = 550 Nm) Illuminates

Multiple Choice

A broad spectrum of light λ = 550 nm) illuminates normally a thin wedge of glass n = 1.50) . If the thick edge of the glass is 0.02 mm, the number of dark fringes observed is

A) 109.
B) 99.
C) 73.
D) 55.
E) 33.