Copy of 24 without work notes H phy student cutnell electomagnetic waves color (1).docx

Copy of 24 without work notes H phy student cutnell electomagnetic waves color (1).docx

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Chapter 24 Electromagnetic waves 24.1 THE NATURE OF ELECTROMAGNETIC WAVES Light has a dual wave-particle nature. A. Wave-particle nature of light wave particle duality 1 Wave-like properties a. Like water waves, light can slightly bend around barriers. b. Light exhibits interference patterns . 2 Particle like properties a. Hot materials give off light(but not the way wave theory predicts) b. Photoelectric effect where some metals give off electrons at certain wavelengths. 3- Electromagnetic waves A. Electrons in an atom vibrate and jump to an excited state then fall back down to the ground state. When an electron moves through space it produces an electromagnetic wave and photon. 24.2 THE ELECTROMAGNETIC SPECTRUM B. Receiving radio waves On a radio the antenna will receive thousands of sine waves. The job of a tuner is to separate one sine wave from the thousands of radio signals that the antenna receives. In this case, the tuner is tuned to receive the 680,000-hertz signal. Tuners work using a principle called resonance. That is, tuners resonate at, and amplify, one particular frequency and ignore all the other frequencies in the air. It is easy to create a resonator with a capacitor and an inductor. The capacitor will start to discharge through the inductor. As it does, the inductor will create a magnetic field.
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Once the capacitor discharges, the inductor will try to keep the current in the circuit moving, so it will charge up the other plate of the capacitor. Once the inductor's field collapses, the capacitor has been recharged (but with the opposite polarity), so it discharges again through the inductor. For more information go to how stuff works how radio works . 1. To find frequency of a wave being transmitted or received. 2.(4) An AM station is broadcasting a radio wave whose frequency is 1600 kHz. The value of the capacitance in Figure 24.5 is 9.2 x 10 -11 F. What must be the value of the inductance in order that this station can be tuned in by the radio? (Answer : L = 1.1 x 10 -4 H)
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3 An AM station is broadcasting a radio wave whose frequency is 1750 kHz. The value of the capacitance in Figure 24.5 is 9.8 x 10 -11 F. What must be the value of the inductance in order that this station can be tuned in by the radio? (Answer : L = 8.4 x 10 -5 H) 4.(3) For an FM radio station broadcasting at a frequency of 102.0 MHz, the capacitance in Figure 24.5 must be adjusted to a value of 25.0 x 10 -12 F. Assuming the inductance does not change, determine the value of the capacitance for an FM station broadcasting at 128.0 MHz. (Answer :C = 1.59 x 10 -11 Farads) 5. For an FM radio station broadcasting at a frequency of 118.0 MHz, the capacitance in Figure 24.5 must be adjusted to a value of 21.0 x 10 -12 F. Assuming the inductance does not change, determine the value of the capacitance for an FM station broadcasting at 132.0 MHz. (Answer :C = 1.68x 10 -11 Farads) B. Lowest frequency of light you can see is red, below that is invisible infrared ( used in heat lamps).
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  • Winter '19
  • Rene Bishop
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