Quiz
Generators of high frequency electromagnetic waves. Frequency ranges used in physiotherapy. Inductive and capacitive methods. Determination of the power of electromagnetic wave sources. Safety technique - Medical Physics -MCQs
Questions in this quiz (20)
1Which of the following human organs and tissues have the least thermal conductivity?
- AMuscles
- BBrain
- CSkin and fat
2Which of the following diagnostic/therapeutic methods cause deep tissue heating?
- AThermography
- BHigh frequency electric current therapy
- CDeep x-ray therapy
3Faradization is a method for:
- AElectro-stimulation with low frequency pulsed current
- BHigh frequency electromagnetic therapy
- CInterferential current therapy of deep-seated tissue
4The most common frequency used in high-frequency electro-stimulation is:
- A20 Hz
- B20 kHz
- C2 MHz
5Modern electromyography methods rely on the following parameter (chose one):
- ARheobase
- BChronaxie
- CAccommodation coefficient
6Thermography is a medical imaging method that:
- AIs harmless
- BHas high resolution
- CWith diagnostic significance similar to MRI
7Which of the following body fluids and tissues has the least electrical conductivity?
- ABlood
- BBones
- CBone marrow
8Electric resistance (R) is inversely proportional to:
- AElectric conductance (G)
- BFrequency (f)
- CPeriod (T)
9What is the main effect that causes heating in microwave diathermy, and also in the microwave oven (f = 2.45 GHz)?
- AResonance: water molecules oscillate with the same frequency
- BDielectric heating: electric dipoles of water are made to rotate
- CRefraction: bending of waves inside the substance
10Electric potential difference is measured in units of volts (V) that represent the ratio of:
- ACharge per time, Q/t
- BEnergy per charge, E/Q
- CEnergy per distance, E/x
11Which of following electric currents is the most dangerous for the human body?
- AHigh frequency AC
- BLow frequency AC
- CPulsed current
12Which of the following currents will cause stimulation in excitable tissue (nerves or muscles)?
- ALow frequency, pulsed, above threshold
- BLow frequency, alternating, below threshold
- CHigh frequency, alternating, above threshold
13High-frequency generators produce electromagnetic waves with:
- AAperiodic behavior
- BConstant amplitude
- CGradually damping amplitude
14Which of the following currents causes differential heating in tissues?
- APulsed current
- BHigh frequency current
- CDC current
15Which of the following features are common forelectrosurgery and electrostimulation?
- AThe frequency
- BThe shape of the electrodes
- CThe use of alternating current
16Specific heat capacity is defined as:
- AThe amount of heat needed to raise the temperature of 1 kg of substance by 1 degree Kelvin (or Celsius)
- BThe heat released during the controlled burn of 1 kg of substance
- CThe heat gain in a substance when Gibbs free energy increases by 1 joule
17Electrosurgical 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?
- AHigh frequencies currents do not penetrate deep enough
- BOscillations are much faster than membrane depolarization time
- CThe power is below stimulation threshold
18What is the heating mechanism of high frequency alternating current (2MHz)?
- ABrief polarization of tissue
- BOscillations of ionized molecules, rotation of dipoles and associated collisions
- CAbsorption of energy from the electromagnetic waves
19When an inductor (L) and a capacitor (C) are connected in series, the resulting (L-C) electric circuit is called:
- AOperational amplifier (compares and amplifies signal)
- BCurrent rectifier (converts AC into DC)
- CHarmonic oscillator (used to emit radio waves)
20The Earth surface is (reasonably) constant potential reference, and for that reason taken to be the :
- AInfinite potential
- BNegative potential
- CZero potential
Information
- Description
- Medical Physics Quiz on Generators of high frequency electromagnetic waves. Frequency ranges used in physiotherapy. Inductive and capacitive methods. Determination of the power of electromagnetic wave sources. Safety technique - Medical Physics -MCQs, created by Hussain Basheer on 23/11/2018.
- Author
- Hussain Basheer
- Language
- English
- Views
- 324
- Tags
- Rating
- No ratings yet Rate this quiz