1. • Response of the eye. The human eye is most sensitive to BIO green light of wavelength 505 nm. Experiments have found that when people are kept in a dark room until their eyes adapt to the darkness, a single photon of green light will trigger receptor cells in the rods of the retina. (a) What is the fre- quency of this photon? (b) How much energy (in joules and eV) does it deliver to the receptor cells? (c) To appreciate what a small amount of energy this is, calculate how fast a typical bacterium of mass 9.5 x 10-12g would move if it had that much energy.

1. • Response of the eye. The human eye is most sensitive to BIO green light of wavelength 505 nm. Experiments have found that when people are kept in a dark room until their eyes adapt to the darkness, a single photon of green light will trigger receptor cells in the rods of the retina. (a) What is the fre- quency of this photon? (b) How much energy (in joules and eV) does it deliver to the receptor cells? (c) To appreciate what a small amount of energy this is, calculate how fast a typical bacterium of mass 9.5 x 10-12g would move if it had that much energy.

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

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28. The resonance frequency of an electron (wa) is related to wavelength (1) of a photon by: wo = 2nc/2 b) wo = c/2 d) wo = 2/c a) c) wo = 1/2 29. The fractional change in energy is represented as: a) ΔΕ b) ΔΕ/Ε c) E – AE d) E + AE 30. In an RLC circuit which quantities exponentially decay with time: a) Charge b) Voltage Both a & b d) None
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Example 2 The CO2 laser is one of the most powerful lasers. The energy difference between the two laser levels is 0.117 eV. Determine the frequency and wavelength of the radiation. Solution:
52. • Structure of a virus. To investigate the structure of BIO extremely small objects, such as viruses, the wavelength of the probing wave should be about one-tenth the size of the object for sharp images. But as the wavelength gets shorter, the energy of a photon of light gets greater and could damage or destroy the object being studied. One alternative is to use elec- tron matter waves instead of light. Viruses vary considerably in size, but 50 nm is not unusual. Suppose you want to study such a virus, using a wave of wavelength 5.00 nm. (a) If you use light of this wavelength, what would be the energy (in eV) of a single photon? (b) If you use an electron of this wavelength, what would be its kinetic energy (in eV)? Is it now clear why matter waves (such as in the electron microscope) are often preferable to electromagnetic waves for studying microscopic objects?
НА • Two copper nanowires are insulated by a copper oxide nano-layer that provides a 10.0- eV potential barrier. Estimate the tunnelling probability between the nanowires by 7.00-eV electrons through a 5.00-nm thick oxide layer. What if the thickness of the layer were reduced to just 1.00 nm? What if the energy of electrons were increased to 9.00 eV? ess Page T 17 System properties 6. EN - ) I hp
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3. • A laser used to weld detached retinas emits light with a BIO wavelength of 652 nm in pulses that are 20.0 ms in duration. The average power expended during each pulse is 0.600 W. (a) How much energy is in each pulse, in joules? In electron volts? (b) What is the energy of one photon in joules? In elec- tron volts? (c) How many photons are in each pulse?
A photon of light has a frequency of 5.00 x 1014 Hz. If the frequency of the photon was doubled then which of these would happen to the energy of this photon? a. it would become one-fourth as much b. it would become half as much c. it would double d. it would quadruple e. it would triple
4) How much energy (in eV's) is an electron using when It generates a frequency of 7.13 e 14 Hz? eV
2. When light with a wavelength of 218 nm is incident on a certain metal surface, electrons are ejected with a maximum kinetic energy of 3.28 x 10 J. Determine the wavelength of light that should be used to quadruple the maximum kinetic -19 energy of the electrons ejected from this surface. X 173.7 nm