Description
week15R: EM in our life more / Radio and TV
1. How Radio Waves Are Produced / antennas https://www.youtube.com/watch?v=eNouTh7S_ys 2. AM and FM radio https://www.youtube.com/watch?v=-qyx8XV8dtE 3. how choose radio station / LC circuit / https://www.youtube.com/watch?v=vhopbp-vMD4 4. CRT-TV https://www.youtube.com/watch?v=K-kxIP3FhCk https://www.youtube.com/watch?v=rwxARHm1Qwk 5. LCD TV https://www.youtube.com/watch?v=0B79dGR19Tg https://www.youtube.com/watch?v=82KaxKyuwV4 https://www.youtube.com/watch?v=k7xGQKpQAWw 6. Plasma TV https://www.youtube.com/watch?v=nNxg90S8Vo8 7. LED TV and OLED TV https://www.youtube.com/watch?v=8quZrUcRFlw 8 Others: industrial generators wind energy https://www.youtube.com/watch?v=DILJJwsFl3w hydro energy https://www.youtube.com/watch?v=Lx6UfiEU3Q0 https://www.youtube.com/watch?v=rnPEtwQtmGQ nuclear energy https://www.youtube.com/watch?v=VrhzkoNU84g https://www.youtube.com/watch?v=_UwexvaCMWA Geothermal Energy https://www.youtube.com/watch?v=mCRDf7QxjDk solar energy https://www.youtube.com/watch?v=wfDWDqyToBg fossil fuel, wood, and coal traditional thermal power https://www.youtube.com/watch?v=IdPTuwKEfmA 9. Others: batteries https://www.youtube.com/watch?v=9OVtk6G2TnQ lead acid battery https://www.youtube.com/watch?v=HhxtfULIO7c dry battery (Zn-based) https://www.youtube.com/watch?v=UEPJXSXw7HA rechargable (Ni-Cd) ? lithium ion ? solar panel ? fuel cell ?
Explanation & Answer
there you go buddy
there you go buddy
Running head: PHYSICS
1
Student name
Student affiliation
PHYSICS
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1. How an antenna works
An antenna transmits or receives electromagnetic waves in form of waves and
troughs, which have different wavelengths of which are also dependent on the
transmitting antennae. Radiated energy is emitted outward from the antenna that produces
it. Half a wavelength is considered a dipole. The electron flow is characterized by
fluctuations in the magnetic fields. It is maximum in a certain direction of flow and
maximum when the direction changes. E and H fields are perpendicular to each other and
represent the time phase and space curvature of the waves. They are reversed in every
half wave while maintaining the direction of progress of the waves – the pointing vector
rule. This rule is reversed when the waves hit a reflective surface. In such a scenario, the
H field remains unchanged while the E field will be reversed, as well as the direction of
propagation of the wave.
2. Wave modulation
Modulation is the process of varying the properties of a high frequency periodic wave
form i.e. the carrier signal to transmit information. It mixes low frequency information
with high frequency information by concealing the low frequency message in a high
frequency wave. Amplitude modulation and frequency modulation are the most popular
modulation techniques.
Modulatory signal
Modulator
Sine signal
carrier
Modulator
carrier
Demodulation
Information
PHYSICS
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Amplitude modulation is dependent on the amplitude and has a narrower frequency band.
High frequency sine wave
Frequency of carrier signal
Amplitude of message signal
Frequency modulation uses the amplitude of the message signal to vary the
frequency of the carrier sine wave. It occupies a wider frequency band.
3. Radio frequency and L.C circuits
Radio waves are transmitted, propagated and received by antennas and converted to
alternating current by and inductor which detect electromagnetic waves. This creates a
magnetic field which in turn is conveyed to a second circuit and produces an alternating
current too. In the second circuit/coil, desired frequencies are transmitted through the
detector diode and sound is heard, while for undesired frequencies, the current is passed
to the ground. L.C. circuits consist of and inductor, a capacitor and an alternating current
PHYSICS
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voltage. The frequency is inversely proportional to (2π) multiplied by the square root
of(inductance × capacitance)
4. Cathode ray t...
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