A series of light pulses, shaped like a cone, subtending an angle θ = 28.0°, is incident on a `light fiber'

Question

A series of light pulses, shaped like a cone, subtending an angle θ = 28.0°, is incident on a `light fiber', as illustrated. The time between pulses is measured just outside the left end of the fiber. If the time between the leading edge of one pulse and the trailing edge of the previous pulse is 39.0 ns, determine how long (L) the fiber can be before the two pulses overlap. (Assume that the fiber has an index of refraction, nglass = 1.52, and a diameter, d=1.34×10-4 m.)
http://www.learning.physics.dal.ca/library/Graphics/Gtype73/cone.gif

A series of light pulses, shaped like a cone, subtending an angle θ = 28.0°, is incident on a `light fiber', as illustrated. The time between pulses is measured just outside the left end of the fiber. If the time between the leading edge of one pulse and the trailing edge of the previous pulse is 39.0 ns, determine how long (L) the fiber can be before the two pulses overlap. (Assume that the fiber has an index of refraction, nglass = 1.52, and a diameter, d=1.34×10-4 m.)
http://www.learning.physics.dal.ca/library/Graphics/Gtype73/cone.gif
just wonderring how the leading edge and trailing edge works.

just wonderring how the leading edge and trailing edge works.

Answer 1

2.65 Meters, dog!