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The lowest frequency light that will produce the photoelectriceffect is called t

ID: 681730 • Letter: T

Question

The lowest frequency light that will produce the photoelectriceffect is called the threshold frequency. a. the threshold frequency for indium is 9.96 x1014 s-1. What is the energy (in J, of aphoton of this radiation? b. Will indium display the photoelectric effect with UV light?With IR light? explain The lowest frequency light that will produce the photoelectriceffect is called the threshold frequency. a. the threshold frequency for indium is 9.96 x1014 s-1. What is the energy (in J, of aphoton of this radiation? b. Will indium display the photoelectric effect with UV light?With IR light? explain

Explanation / Answer

(a) Recall that the energy of a photon is given by E=hv where h isPlancks constant (6.626*10^-34 J/s) and v is frequency. E=(6.626*10^-34 J/s)(9.96*10^14 s^-1) = 6.6*10^-19J (b) Since the threshold frequency is the lowest frequency of lightthat will produce the photoelectric effect, like you stated, youneed to compare your threshold frequency (9.96*10^14 s^-1) withlight from the UV and IR range. The UV light range is 10-400nm so (using c=v) that means thefrequency range is 7.5*10^14 to 3*10^16 s^-1 range. The IR light range is 400-700nm so it's frequency range is4.3*10^14 to 7.5*10^14 s^-1. As the numbers show, certain frequencies (high freq UV) of UV lightwill trigger the photoelectric effect where IR will not trigger itat all because the entire range of IR light has frequencies thatare lower than your threshold frequency.