Physics Chapter on Radioactivity and Waves

Radioactive Counting Error

• If radioactive counting is measured for four times longer with constant activity, the absolute error doubles.

SI Units

• Speed and weight are not SI units.

Stochastic Biological Effect

• The frequency of the stochastic biological effect increases as the dose increases.
• This effect is heritable.

Light Ray Direction Change in Eye

• The direction of a light ray passing through the human eye changes most significantly at the cornea.

Volume Velocity of Viscous Liquid

• Volume velocity is directly proportional to the pressure difference.

Sound Source Approaching Detector

• If the sound source approaches the detector, the detected frequency is higher than the emitted frequency.
• Stokes' law states that the diffusion constant is inversely proportional to the viscosity of the medium.

Blood Dilution Isotopes

• ⁵¹Cr and ¹³¹I are used to measure blood dilution volume.

True Statements Regarding Alpha Particles

• Alpha particles are high-energy photons.
• Alpha particles are NOT protons.

EEG Waves in Resting Brain

• The resting brain emits alpha waves.

Refractive Index of Biconcave Lens

• A biconcave lens is a diverging lens.
• The refractive index of the lens is greater than the refractive index of the medium.

Imaging Equipment and Brain Resolution

• In CT imaging, absorption by the skull impairs the resolution of brain images.

Laplace Law

• The Laplace law states that in the wall of a pipe with a circular cross-section, the tension created by the pressure in the pipe.

Blood Pressure Change During Standing

• Blood pressure decreases in the brain of a person who stands up suddenly.

Laminar Blood Volume Velocity in a Blood Vessel

• Doubling the radius of a blood vessel doubles the volume velocity of laminar blood flow.

Imaging Procedure and Ionizing Radiation

• CT and PET imaging procedures use ionizing radiation to create images.

Dark-Adapted Eye Sensitivity

• The dark-adapted eye is the most sensitive.

Coherent Light Wave Interference

• Two light waves cause permanent interference if they are coherent and have a constant phase difference.

SI Unit of Decay Constant

• The SI unit of decay constant is 1/s (per second).

Korotkoff Noise

• Korotkoff noise occurs when the air bag pressure drops below the pressure generated by the heart's peak pressure.

Ionizing Radiation and Biological Effect

• With the same transmitted energy, 3 MeV alpha radiation has the greatest biological effect.

Ultracentrifugation and Frictional Coefficient

• In ultracentrifugation, the lower the frictional coefficient, the faster the movement.
• The lower the diffusion constant, the slower the movement.

Positron Beta Decay

• In positron beta decay, the atomic number increases by one, and the mass number remains unchanged.

Effective Half-Life of Radioactive Isotope

• The effective half-life of a radioactive isotope introduced into the body is less than the biological half-life.
• It is equal to the reciprocal of the sum of the reciprocals of the two half-lives (biological and physical).

Types of EEG Waves

• Delta waves have an amplitude in the range of 50 to 100 μV.

Isotope Decay Percentage

• After 20 minutes, 75% of a 10-minute half-life ¹³N isotope has decayed.

Isotope Decay Percentage

• After 40 minutes, 6.25% of a 10-minute half-life ¹⁴N isotope has not decayed.

Combination of Refractive Index

• The refractive index of a lens system consisting of two thin lenses in contact is the sum of the refractive indexes of each lens.

Radioactive Source Activity

• Radioactive source activity is the number of radioactive decays per second.

Stokes Law

• Stokes' law gives the magnitude of the medium resistance force acting on a spherical body moving in a viscous liquid.

Imaging Procedures and Electromagnetic Radiation

• Echoencephalography does NOT use electromagnetic radiation to create images.

Diffusion Constant Dependence

• The diffusion constant, D, depends on the shape of the diffusing particle, as well as temperature.

SI Unit for Viscosity

• The SI unit for viscosity is kg/ms (kilograms per meter per second).
• The degree of refraction at the boundary of two media depends on the relative refractive index of one medium to another, and the density of the two media.

Sound Transmission and Frequency

• The transmission capacity of high-frequency sounds is lower than that of low-frequency sounds.
• Radiated sounds can be characterized as deep or shallow sounds.

Wavelength of Electron

• The wavelength of an electron accelerated in a vacuum by 1.5V is approximately 0.3 µm.

Light Wave Interference

• Two light waves cause permanent interference if they are coherent and have a constant phase difference.

SI Unit of Time

• The Sl unit of time is the second.

Thyroid Examination Activity

• The usual activity of a ¹³¹I source used in thyroid examinations is 0.4 MBq.

Beta Particles

• Beta particles are electrons or positrons

Voltage Clamp Technique

• The Voltage-clamp technique maintains the membrane voltage at a specific pre-set value.

EEG Wave Amplitude

• Beta waves in EEG have an amplitude of less than 20µV.

Error Calculation for Difference of Two Quantities

• The absolute error in the difference of two quantities is calculated by taking the square root of the sum of the squares of the absolute errors in each quantity.

Radioactive Decay Constant

• The radioactive decay constant, k, is inversely proportional to the half-life (t_1/2) of the substance.

Microwave Diatermy Frequency

• Microwave diatermy uses 2540 MHz frequency.

Hypertonic Infusion

• Hypertonic infusion solutions can cause plasmolysis in cells.

Beta Particle Properties (False Statements)

• Beta particles are NOT high-energy photons.
• Beta particles are NOT hydrogen nuclei.

SI Unit of Radiation Doses

• The SI unit for radiation dose is C/kg (Coulombs per kilogram).

Condenser Space Diathermy

• The frequency for condenser space diathermy is 0.03 GHz.

Object within Focal Length of Converging Lens

• A real object placed within a converging lens' focal length will produce a virtual, upright image.

Diffusion Constant Factors

• The diffusion constant does NOT depend on the density of the medium or the pH of the medium.

Alpha Particles

• Alpha particles are doubly ionized helium atoms (he nuclei).