Question

Fred points a toy laser gun at a wall. Considering that the frequency of the gun's light is 4.91 × 1014 hertz and that Planck’s constant is 6.61 × 10-34 joule·seconds, what is the energy of the laser light?
A) 3.24 × 10-21 joules
B) 4.91 × 1015 joules
C) 2.04 × 10-21 joules
D) 4.92 × 10-18 joules

Answer 1

E=hf 

E=6.61x10^34x4.91x10^14 
E=3.24x10^21 joules 

Answer is A 

Answer 2

The answer is 3.24 x 10^-21