Test on X-rays and the X-ray machine

Question 1: Characteristic X-ray emission peaks result from electrons transitioning between atomic shells in the anode material.

A. Yes

B. No

Explanation: The study materials state that characteristic X-ray peaks correspond to X-rays emitted when electrons transition between atomic shells in the anode material.

Question 2: According to the Duane-Hunt law as presented in the study materials, what is the relationship between the minimum wavelength (λ_min) of X-rays produced and the accelerating voltage (U)?

A. The minimum wavelength is directly proportional to the square of the accelerating voltage.

B. The minimum wavelength is inversely proportional to the accelerating voltage.

C. The minimum wavelength is constant regardless of the accelerating voltage.

D. The minimum wavelength is directly proportional to the accelerating voltage.

Explanation: The study materials explicitly state that the minimum wavelength (λ_min) of the X-rays produced is inversely proportional to the accelerating voltage (U), as given by the Duane-Hunt law: λ_min = hc / (eU). This formula shows the inverse relationship between λ_min and U.

Question 3: Pair production is a relevant interaction mechanism in diagnostic X-ray imaging.

A. Yes

B. No

Explanation: Pair production requires very high-energy X-ray photons (above 1.022 MeV), an energy level not typically used in diagnostic X-ray imaging, rendering this effect irrelevant for such applications.

Question 4: An X-ray beam with an initial intensity (I₀) of 200 units passes through a 3.0 cm thick layer of tissue. If the linear attenuation coefficient (μ) for this tissue at the given X-ray energy is 0.20 cm⁻¹, what is the approximate intensity (I) of the X-ray beam after passing through the tissue?

A. 200 units

B. 109.76 units

C. 140 units

D. 320 units

Explanation: To calculate the intensity of the X-ray beam after passing through the material, use the exponential attenuation law: I = I₀ · e^(−μx). Given I₀ = 200 units, μ = 0.20 cm⁻¹, and x = 3.0 cm. Plugging these values into the formula: I = 200 · e^(−0.20 cm⁻¹ × 3.0 cm) = 200 · e^(−0.6). Calculating e^(−0.6) ≈ 0.5488. Then, I = 200 · 0.5488 ≈ 109.76 units. Therefore, the approximate intensity of the X-ray beam after passing through the tissue is 109.76 units.

Question 5: The focusing cup directs the emitted electrons away from the anode.

A. Yes

B. No

Explanation: The study materials state that the focusing cup 'directs the emitted electrons towards the anode.'