A simple string light produces 10 J of light energy each second. What is the efficiency of the light bulb if it uses up 200 J each second? Show work

A. 5%
B. 10%
C. 20%
D. 25%

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explanation:

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray

the right answer is 0.3 meters per second