Tag Archives: Electromagnetic radiation

Waves,Properties and Their Applications.

4 Sep
  1. Doppler Sim 1.0

    Doppler Sim 1.0 (Photo credit: J.Gabás Esteban)

    316/365 Revision Week: Partial Differential Eq...

    316/365 Revision Week: Partial Differential Equations (Photo credit: stuartpilbrow)

    Electromagnetic Spectrum

    Electromagnetic Spectrum (Photo credit: hummingcrow)

    Change of wavelength caused by motion of the s...

    Change of wavelength caused by motion of the source. (Photo credit: Wikipedia)

    The principle of many refractometers.

    The principle of many refractometers. (Photo credit: Wikipedia)

    longitudinal wave

    longitudinal wave (Photo credit: mhobl)

    English: Propagation of a plane compression wa...

    English: Propagation of a plane compression wave (impulse); made with Scilab and Jasc Animation Shop 2.02 Deutsch: Vorstellung einer Longitudinalwelle (impuls); gemacht mit Scilab und Jasc Animation Shop 2.02 Français : Propagation d’une onde de compression plane (impulsion) ; créé avec Scilab et Jasc Animation Shop 2.02 (Photo credit: Wikipedia)

    Doppler-Effekt Animation

    Doppler-Effekt Animation (Photo credit: Wikipedia)

    Total internal reflection in a bar of PMMA. Th...

    Total internal reflection in a bar of PMMA. The laser is HeNe laser (Photo credit: Wikipedia)

    Illustration of Wave equation

    Illustration of Wave equation (Photo credit: Wikipedia)

    Total internal reflection

    Total internal reflection (Photo credit: Wikipedia)

    English: Compressional wave (longitudinal wave...

    Refractive Indices
    Refractive Indices (Photo credit: the_himay)
    English: Illustration of wavefronts in the con...

    English: Illustration of wavefronts in the context of Snell’s law. (Photo credit: Wikipedia)

    Understand and use the terms amplitude, frequency, period, speed and wavelength

  1. Identify the different regions of the electromagnetic spectrum and describe some of their applications.
  1. Use the wave equation v = fλ.
  1. Recall that a sound wave is a longitudinal wave which can be described in terms of the displacement of molecules.
  1. Use graphs to represent transverse and longitudinal waves, including standing waves.
  1. Explain and use the concepts of wavefront, coherence, path difference, superposition and phase.
  1. Recognize and use the relationship between phase difference and path difference.
  1. Explain what is meant by a standing (stationary) wave, investigate how such wave is formed, and identify nodes and antinodes.
  1. Recognize and use the expression for refractive index 1μ2  = sin i/sin r = v1/v2 determine refractive index for a material in the laboratory, and predict whether total internal reflection will occur at an interface using critical angle.
  1. Investigate and explain how to measure refractive index.
  1. Investigate and explain how to measure the rotation of the plane of polarization.
  1. Investigate and recall that waves can be diffracted and that substantial diffraction occurs when the size of the gap or obstacle is similar to the wavelength of the wave.
  1. Explain how diffraction experiments provide evidence for the wave nature of elections.
  1. Discuss how scientific ideas may change over time, for example, our ideas on the particle/wave nature of electrons.
  1. Recall that, in general, waves are transmitted and reflected at an interface between media.
  1. Explain how different media affect the transmission/reflection of waves travelling from one medium to another.
  1. Explore and explain how a pulse-echo technique can provide details of the position and/or speed of an object and describe applications that use this technique.
  1. Explain qualitatively how the movement of a source of sound or light relative to an observer/detector gives rise to a shift in frequency (Doppler Effect) and explore applications that use this effect.
  1. Explain how the amount of detail in a scan may be limited by the wavelength of the radiations or by the duration of the pulses.
  1. Discuss the social and ethical issues that need to be considered, e.g., when developing and trailing new medical techniques on patients or when funding a space mission.

The Nature of Particles

21 Aug
Radiation Scan

Radiation Scan (Photo credit: FastLizard4)

Classical physics (Rayleigh–Jeans law, black l...

Black body radiation for T=287K, which is the ...

Black body radiation for T=287K, which is the temperature of the earth. (Photo credit: Wikipedia)

English: Black body curves of Planck for vario...

English: Black body curves of Planck for various temperatures and comparison with classical theory of Rayleigh-Jeans. Italiano: Confronto fra le curve del corpo nero della teoria di Planck e della teoria classica di Rayleigh-Jeans. (Photo credit: Wikipedia)

The nature of particle.

1.Thomson concluded that those cathode rays were made up of particles.

2. Max Planck was trying to find out a model to understand the way in which a black body emits radiation.

3. Black body is perfect emitter and absorber of electromagnetic radiation.

4. He found that this was possible only if he had assumed radiations were emitted in packets.

5. Plank’s idea was not understood until Einstein, 1905 showed that black body radiation could be understood better if it was assumed that the radiation itself was quantised,  consisting of particle like packets of energy.

6.Each is referred to as photon.

Ultraviolet catastrophe:  Classical physics can predict that black body radiation based on long wavelength but not at short wavelengths, leading a disagreement that physicist calls as U.V catastrophe.

 

 Radiation Flux —Do the worked out example.

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