الفيزياء الحيوية الطبية Medical Biophysics ا.م.د/هالة مصطفى احمد

Optics Optics: It is describe the behavior of visible light as well as infrared and ultraviolet light, which are similar to visible light but are not detectable by the human eye. Ex:X-rays, microwaves, and radio waves can be described with optical principles because all of these, along with visible light, are types of electromagnetic waves.

It light is modeled as an electromagnetic wave composed of oscillating Classical optics It light is modeled as an electromagnetic wave composed of oscillating electric andmagnetic fields

Types of Classical optics 1-Geometrical optics 2-Waves optics

Geometrical optics:- 1-Geometrical optics describes light propagation . 2-A light ray is perpendicular to the light's wavefronts (and therefore collinear with the wave vector). 3-Light rays bend at the interface between two dissimilar media and may be curved in a medium in which the refractive index changes

Reflections:- Specular reflection Diffuse reflection

Specular reflection 1-Specular reflection describes glossy surfaces such as mirrors, which reflect light in a simple. 2-Reflected images that can be associated with an actual (real) or (virtual) location in space.

Diffuse reflection:- 1-Diffuse reflection describes matter surfaces, such as paper or rock. 2-The reflections from these surfaces can only be described statistically, with the exact distribution of the reflected light depending on the microscopic structure of the surface

Optical Instruments:- Microscopes 1-Microscopes were first developed with just two lenses: an objective lens and an eyepiece. 2-The objective lens is essentially a magnifying glass and was designed with a very small focal length while the eyepiece generally has a longer focal length.

CHAPTER (2) WAVE MOTION

WAVE MOTION 1: Definition. A wave is a disturbance that propagates through space and time, usually with transference of energy

Types of Waves Motion 1-Mechanical waves optics 2-Electromagnetic waves optics 3-Matter waves optics

1-Mechanical waves optics Mechanical wave optics require a material medium to travel (air, water, ropes).

1-Mechanical waves optics These waves are divided into three different types. 1-Transverse waves the medium to move perpendicular to the direction of the wave. 2-Longitudinal waves the medium to move parallel to the direction of the wave. 3-Surface waves are both transverse waves and longitudinal waves mixed in one medium

2-Electromagnetic waves optics Electromagnetic waves optics do not require a medium to travel (light, radio).

3-Matter waves optics 3-Matter waves optics Matter waves optics are produced by electrons and particles.

Measuring Waves optics 1-Periodic Time The time taken by the vibrating body to complete one vibration. 2-Frequency It is the number of complete vibrations per second, in hertz (Hz). f = 1 / T 3- Wavelength Wavelength (λ) is the length of one complete cycle, in m or cm.

Measuring Waves optics 4-Velocity By knowing the frequency of a wave and its wavelength, we can find its velocity. v = f λ

Measuring Waves optics 5-Amplitude The amplitude is maximum displacement of vibrating body

Moving from one medium to another Once a wave (incident wave) has reached the end of a medium Part of the energy is transferred to the medium that is immediately next to it (transmitted wave) Part is reflected backward (reflected wave). The energy transferred depends on the difference between the mediums.

Collision of waves 1:Constructive interference 2:Destructive interference

1:Constructive interference It is when the amplitudes of the initial waves are in the same direction. The resulting wave will be larger than the original waves. The highest point of a constructive interference is called an anti node.

2:Destructive interference It is when the amplitudes of the initial waves are opposite. The amplitude of the resulting wave will be zero. The point in destructive interference is called a node

CHAPTER (3) SPECTROSCOPY

Spectroscopy Spectroscopy. Spectroscopy was the study of the interaction between radiation and matter as a function of wavelength.

Classification of methods. 2-1:Nature of excitation measured. 1-Electromagnetic spectroscopy interactions of matter with electromagnetic radiation, such as light. 2-Electron spectroscopy interactions with electron beams.

3-Dielectric spectroscopy involves the frequency of an external electrical field 4-Mechanical spectroscopy involves the frequency of an external mechanical stress.

Measurement process 1-Absorption spectroscopy uses the range of the electromagnetic spectra in a substance absorbs. This includes atomic absorption spectroscopy ( infrared spectroscopy)

2-Emission spectroscopy uses the range of electromagnetic spectra in a substance radiates (emits). The substance first must absorb energy. (spectro fluorimetry)

3-Scattering spectroscopy measures the amount of light that a substance scatters at certain wavelengths, incident angles, and polarization angles. The scattering process is much faster than the absorption/emission process. (Raman spectroscopy)

Story problems 1-A radio wave has a frequency of 83.8 MHz (83.8 x 106 Hz). What is its period?

Story problems f =83.8 x 106 Hz f = 1 / T T = 1 / f T = 1 / 83.8 x 106 Hz T = 1.1 x 106 s

Story problems 2-The light wave velocity in space is 3 x 105 Km/s given that the wavelength of light is 5000Aº. Find the frequency of light?

Story problems V = 3 x 105 Km/s = 3 x 105 x 103 = 3 x 108 m/s λ = 5000Aº = 5000 x 10-10 = 5000 x 10-7 m v = f λ f = v/ λ = 3 x 108 m/s / 5000 x 10-7 m = 6 x 1014 Hz.

Story problems 3-The velocity of a wave is 420 m/s. If the frequency of the wave is 85 Hz, what is its wavelength?

Story problems V = 420 m/s f = 85 Hz v = f λ λ = v/f = 420 m/s / 85 Hz

Story problems 4-If a wave with a wavelength of 5.0 m has a 3.0 x 10-3 s period, a. what is its frequency? b. what is its velocity?

Story problems T = 3.0 x 10-3 s λ = 5 m f=? f = 1 / T f = 1 / 3 x 10-3 s f = 3 x 10-2 Hz v = f λ v = f λ = 3 x 10-2 Hz X 5 m V = 15 x 10-2 m/sec

5)What are the types of excitation measured of spectroscopy?

6)What are the types of Waves Optics? 7)What are the factors effects on measuring waves optics?

8)Deine each of the following: 1-Spectroscopy

Read and mark ( √ )the correct answer: 1-Which type of electromagnetic waves has the greatest: a-Radio waves b-Visible light c-X-rays

2-Which of the following is not an electromagnetic waves: a-Sound b-Radio c-Light

3-light waves are : a-Transverse waves b-Longitudinal waves c-rotating waves

10) Compare between: 1)Electromagnetic spectroscopy and Electron spectroscopy 2)Constructive and Destructive collision

1)Electromagnetic spectroscopy and Electron spectroscopy Interactions with electron beams Interactions of matter with electromagnetic radiation Interactions kinetic energy Intensity of energy No kinetic energy Measurement

2)Constructive and Destructive collision Items opposites Same direction Amplitude zero large Resulting Waves anode Anti node The point interference

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