16129396
Descrição
Quiz por Hussain Basheer, atualizado more than 1 year ago
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Criado por Hussain Basheer
mais de 5 anos atrás
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Questão 1
Questão
Which of the following human organs and tissues have the least thermal conductivity?
Responda
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Muscles
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Brain
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Skin and fat
Questão 2
Questão
Which of the following diagnostic/therapeutic methods cause deep tissue heating?
Responda
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Thermography
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High frequency electric current therapy
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Deep x-ray therapy
Questão 3
Questão
Faradization is a method for:
Responda
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Electro-stimulation with low frequency pulsed current
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High frequency electromagnetic therapy
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Interferential current therapy of deep-seated tissue
Questão 4
Questão
The most common frequency used in high-frequency electro-stimulation is:
Responda
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20 Hz
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20 kHz
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2 MHz
Questão 5
Questão
Modern electromyography methods rely on the following parameter (chose one):
Responda
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Rheobase
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Chronaxie
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Accommodation coefficient
Questão 6
Questão
Thermography is a medical imaging method that:
Responda
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Is harmless
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Has high resolution
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With diagnostic significance similar to MRI
Questão 7
Questão
Which of the following body fluids and tissues has the least electrical conductivity?
Responda
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Blood
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Bones
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Bone marrow
Questão 8
Questão
Electric resistance (R) is inversely proportional to:
Responda
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Electric conductance (G)
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Frequency (f)
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Period (T)
Questão 9
Questão
What is the main effect that causes heating in microwave diathermy, and also in the microwave oven (f = 2.45 GHz)?
Responda
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Resonance: water molecules oscillate with the same frequency
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Dielectric heating: electric dipoles of water are made to rotate
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Refraction: bending of waves inside the substance
Questão 10
Questão
Electric potential difference is measured in units of volts (V) that represent the ratio of:
Responda
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Charge per time, Q/t
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Energy per charge, E/Q
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Energy per distance, E/x
Questão 11
Questão
Which of following electric currents is the most dangerous for the human body?
Responda
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High frequency AC
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Low frequency AC
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Pulsed current
Questão 12
Questão
Which of the following currents will cause stimulation in excitable tissue (nerves or muscles)?
Responda
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Low frequency, pulsed, above threshold
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Low frequency, alternating, below threshold
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High frequency, alternating, above threshold
Questão 13
Questão
High-frequency generators produce electromagnetic waves with:
Responda
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Aperiodic behavior
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Constant amplitude
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Gradually damping amplitude
Questão 14
Questão
Which of the following currents causes differential heating in tissues?
Responda
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Pulsed current
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High frequency current
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DC current
Questão 15
Questão
Which of the following features are common forelectrosurgery and electrostimulation?
Responda
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The frequency
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The shape of the electrodes
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The use of alternating current
Questão 16
Questão
Specific heat capacity is defined as:
Responda
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The amount of heat needed to raise the temperature of 1 kg of substance by 1 degree Kelvin (or Celsius)
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The heat released during the controlled burn of 1 kg of substance
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The heat gain in a substance when Gibbs free energy increases by 1 joule
Questão 17
Questão
Electrosurgical procedures apply alternating current in the radio frequency (RF) range (100 kHz - 5 MHz) directly to the tissue. Why during electrosurgery there is no nerve and muscular stimulations?
Responda
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High frequencies currents do not penetrate deep enough
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Oscillations are much faster than membrane depolarization time
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The power is below stimulation threshold
Questão 18
Questão
What is the heating mechanism of high frequency alternating current (2MHz)?
Responda
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Brief polarization of tissue
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Oscillations of ionized molecules, rotation of dipoles and associated collisions
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Absorption of energy from the electromagnetic waves
Questão 19
Questão
When an inductor (L) and a capacitor (C) are connected in series, the resulting (L-C) electric circuit is called:
Responda
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Operational amplifier (compares and amplifies signal)
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Current rectifier (converts AC into DC)
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Harmonic oscillator (used to emit radio waves)
Questão 20
Questão
The Earth surface is (reasonably) constant potential reference, and for that reason taken to be the :
Responda
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Infinite potential
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Negative potential
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Zero potential
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