This question has mistakes.the correct question is
The blue laser in a blue ray DVD player is 405nm laser in vacuum. The aser strikes a quartz crystal with index of refraction 1.46 at normal incidence. The power of the laser is 0.25W and I'm guessing the beam is circular with radius 0.1mm. What is the intensity of the light transmitted into the crystal? Select One of the Following:
(a) 7.7 x 10⁶ W/m²
(b) 1.5 x 10⁶ W/m²
(c) 6.5 x 10⁶ W/m²
(d) 2.85 W/m²
(e) Toby.
Answer:
(a) 7.7 x 10⁶ W/m² Correct
Explanation:
The Intensity of laser is given as
The incident index of refraction and transmitted is
Aaron's car is moving at speed of 30 m/s
His reaction time is given as 0.7 s
but when he is tired the reaction time is doubled
Now we need to find the distance covered by his car when he is tired during the time when he react to apply brakes
So here since during this time speed is given as constant so we can say that distance covered can be product of speed and time
So here we can use
So the car will move to 42 m during the time when he apply brakes