Activity 18: Scientific Notation and Calculation Practice -­‐x 10 = divide by 10x = move decimal x places to the left
x
10 = multiply by 10x = move decimal x places to right
PART ONE: Convert to and from scientific notation 1. Convert from scientific notation to regular form 5.324 x 10-­‐6 m 1.824 x 105 m **What part of the EM spectrum is each wavelength in? 2. Convert from regular form to scientific notation 4,375,000 m 0.000000725 m 300,000,000 s-­‐1 PART TWO: Converting between different measurements To convert between units: (for example, how many meters in 20 cm?) 1. Take the units you have (e.g., 20 cm) 2. Find the the conversion factor (e.g., 0.01 m = 1 cm, so the conversion factor is 0.01 m/cm). 3. Multiply by the conversion factor so that your units cancel out !.!" !
(e.g. 20 𝑐𝑚 × ! !" = 20 ×0.01 𝑚 = 0.2 𝑚 ) How many pennies are in three dollars? Show your work, using the method demonstrated in lecture. How many nanometers are in 20 m? PART THREE: Understanding frequency units You have a frequency of 300,000,000 s-­‐1. How many Hertz do you have in scientific notation? What part of the EM spectrum is this frequency in? PART FOUR: Calculations of wavelength and frequency c = λ*f; in air/vacuum: c = 3*108 m/s 1. Calculate the wavelength of radiation emitted from radioactive cobalt with a
frequency of 2.80 x 1020 s¯1. What region of the eletromagnetic spectrum does this lie
in?
2. 1.50 x 1013 Hz? Does this radiation have a longer or shorter wavelength than red
light?
3. Light with a frequency of 7.26 x 1014 Hz lies in the violet region of the visible
spectrum. What is the wavelength of this frequency of light? Answer in units of nm.
4. When an electron beam strikes a block of copper, x-rays of frequency 1.07 x 1019 Hz
are emitted. What is the wavelength of these x-rays? Answer in units of pm.
5. Calculate the wavelength (in meters) of radiation a frequency of 5.00 x 1014 s¯1.
6. The radio station KUSC (in Southern California) broadcasts at 91.5 MHz. Calculate
its wavelength in meters.