A Light Beam Traveling Horizontally Enters a Hole in the Side

Multiple Choice

A light beam traveling horizontally enters a hole in the side of a laboratory on planet X. The laboratory is 40.0 m wide. If the light beam hits the far wall a distance 0.20 mm below the height it entered the laboratory, what is the acceleration of gravity on planet X?

A) 2.25 × 10¹⁰ m/s²
B) 8.00 × 10⁶ m/s²
C) 9.81 m/s²
D) 4.50 × 10⁵ m/s²
E) 3.75 × 10³ m/s²