Number 11 in context of number 10 8. According to Einstein\'s photo electric eff
ID: 553101 • Letter: N
Question
Number 11 in context of number 10
8. According to Einstein's photo electric effect, as long as a single photon of light of sufficient energy hits a metal surface, an electron will be ejected. This minimum threshold energy is called the work function, , write down the equation that indicates how fast an electron moves once ejected from a metal surface. 9. The amount of energy contained within a single photon is determined with which equatio n? 10. Calculate the energy per photon of a blue laser pointer with a wavelength of 410 nm. 4845 x10-19 J 11. If a 5mW (m//s) laser made of the same light as that of question 10 is kept on. How long will two AAA batteries each containing 5 kJ of energy last?Explanation / Answer
Ans 11> The power of the laser pointer is 5mW = 5 mJ/s = 0.005 J/s
Two batteries of 5kJ energy means a total energy of 10kJ = 10 x 103 J
Therefore the time lasted by these batteries are (total energy)/(power) = (10 x 103 )/ 0.005 = 2 x 106 s = (2x106)/3600 hours =555.55 hours = 23 days approx
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.