Answer is 1 molecule of S
The hotter star will be 16 times more luminous - luminosity depends on two things - the size of the star and the temperature of the star. The hotter a star is, the more energy it will give out. This will give rise to greater luminosity.
Explanation:
Let east direction is negative and west direction is positive. The acceleration of an object is given by :

Where
v is the final speed
u is the initial speed
t is the time taken
As the car decelerates, the final speed of the car is less as compared to the initial speed. As a result, its acceleration is negative. It means the car travels eastward and slows down. Hence, this is the required solution.
The sun is the primary source of light. Other artificial sources are light bulb, torch light and some others. Thats all i can think of.