Humboldt State University ® Department of Chemistry

Richard A. Paselk

	General Chemistry	Spring 2011
Exercise: Light & Energy	© R. Paselk 2008
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Light and Energy

Speed of light in vacuo = c = 2.9979 x 108m/s	c = f•
Plank's constant = h = 6.626 x 10-34J*s	Ephoton = hf = hc/
J = kg m2s-2	= h/mv
	E= mc2

1. What is the frequency of light with a wavelength of 650.4 nm?

2. What is the wavelength of a photon which has a frequency of 90.50 MHz?

3. KHSU broadcasts at 90.50 MHz.

a. Find the energy of one KHSU photon.

b. If KHSU has a 9,000 watt transmitter how many photons does it release each second (one watt = one J/sec)

4. Find the wavelength of a ¹²C atom moving at 2 m/sec.

Answers 1-4

In addition to these exercises you should familiarize yourself with the text materials referenced below.

• Sections 7.1-7.2 (pp 275-284), in your textbook-you should be able to do the approprite examples and exercises in the assigned problems listed on the Schedule.

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© R A Paselk

Last modified 10 March 2009