# Power and Speed

## Homework Statement

Every 2km power is reduced by half. Initial power = 10watt. What is power after travelled 8km?

C = 3x108. What is speed of light passing through optic fibre? n = 1.55

## Homework Equations

P = $$\frac{w}{T}$$ ?

## The Attempt at a Solution

I dont know where to start

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