A Broad Spectrum of Light $\lambda$ = 550 Nm) Illuminates Normally a Thin Wedge of Glass

Multiple Choice

A broad spectrum of light ( $\lambda$ = 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