true and false-14
All types of electromagnetic waves are physically similar, differing only in frequency and wavelength
T
Absorption of a photon will occur only when the quantum energy of the photon precisely matches the energy gap between the initial and final states
T
In the microwave diapason, the quantum energies of the photons cause molecular rotation and torsion, which is perceived as heat.
T
Ultraviolet radiation causes molecular vibration: periodic stretching or torsion of internal molecular bonds.
F
Infrared radiation is absorbed more strongly than radio waves and has less depth of penetration
T
In the visible and ultraviolet ranges the quantum energies are large enough to cause excitation. These types of radiation are absorbed strongly and
generally penetrate through the skin
F
One common misconception is that microwaves can produce radiation damage similar to that produced by x-rays and nuclear radiation.
T
Any hot object gives off microwave radiation.
F
Infrared waves penetrate very far into the body and are suitable when the therapeutic effect desired is the warming of deep tissues.
F
Infrared photography has been used to study the pattern of healing under a scab and for eye diagnostics.
T
The quantum energies of ultraviolet photons are such that they are absorbed strongly by most forms of matter, even air.
T
Ultraviolet rays usually do not penetrate into tissue deeper than about 10mm.
T
Ultraviolet radiation is used therapeutically for treating skin conditions such as psoriasis and acne
T
In the x-ray tube, different electrons may be accelerated at different rates. Hence, x-rays can be produced with a wide spread of wavelengths
F
In Compton scattering, the incident x-ray photon gives only a friction of its energy to the excited electron, with the remainder „scattering“ off as a lower energy photon. This scattered photon will have a higher frequency and longer
wavelength.
F
In an x-ray tube, when a high speed electron approaches a metal atom from the metal target, it is strongly attracted and accelerated by the electron cloud of the atom, thereby losing kinetic energy.
F
The upper ultraviolet part of the electromagnetic spectrum, x-rays and gamma rays are considered ionizing radiation.
T
Since barium strongly absorbs x-rays, barium sulfate is used for the examination of the upper and lower gastrointestinal tract
T
X-ray tomography is used to observe the motion of internal parts of the body
F
In the intense magnetic field of the NMR scanner, the magnetic moments of hydrogen nuclei can take two alignments: either along the magnetic field vector in a higher energy state or against the magnetic field in a lower energy
state.
F
The NMR technique is very promising for future clinical applications because of the fact that the rate of decay from high to low state is quite different for different physicochemical environments of the hydrogen atoms.
T
The important feature of laser light which makes it valuable for medical purposes is its collimation in a very narrow beam of light which can be further focused to a microscopic point, thus concentrating a huge amount of energy in
the focus.
T
The discovery of the laser was essentially the discovery of how absorption could be practically achieved.
F
To increase the laser efficiency it is important to have the light pass through the laser medium several times
T
The laser beam is made up of very nearly parallel rays and contains several wavelengths of light.
F
Holography, a type of two-dimensional photography, has many potential applications in medicine.
F
Holography can provide better resolution than a standard microscope of a similar magnifying power
T
A hologram cannot be made with ordinary light because such light is „coherent“.
F
According to classical physics, any charged particle, when it is accelerated, emits energy in the form of electromagnetic wave.
T
The characteristic x-rays depend on the voltage applied to the tube.
T