A sample of plutonium decays to 25% of its original mass in 30 h. Find the half-life of this sample. a. 15 h b. 75 h c.60 h d. 45 h 2) Fog can greatly reduce the intensity of oncoming headlights. The distance, d, in metres, of an oncoming car whose headlights have an intensity of light, I, in lumens (Im), is given by d = -167log (1/125). a. How far away is a car whose headlight intensity is 50lm? b. If an oncoming car is 30m away, what is the intensity of its headlights? c. If the headlight intensity doubles, does this mean the car is half as far away? Explain