Test on X-rays: questions for medical school entrance exams

Question 1: In the Photoelectric Effect, the entire energy of the incoming X-ray photon is absorbed by the atom.

A. Yes

B. No

Explanation: The study materials state that in the Photoelectric Effect, 'The entire energy of the X-ray photon is absorbed by the atom.'

Question 2: According to the study materials, how does the intensity of an X-ray beam change as it passes through a material?

A. It decreases linearly.

B. It increases exponentially.

C. It decreases exponentially.

D. It remains constant.

Explanation: The study materials state that 'The intensity of an X-ray beam decreases exponentially as it passes through a material.' This directly answers the question about how the intensity changes.

Question 3: In the formula for X-ray attenuation, I = I₀ · e^(-μx), the term 'e' represents the initial energy of the X-ray photons.

A. Yes

B. No

Explanation: The study materials state that 'e' is the base of the natural logarithm (approximately 2.718), not the initial energy of the X-ray photons.

Question 4: According to the provided study materials, which formula correctly calculates the Equivalent Dose (H)?

A. H = D / W_R

B. H = D · W_R

C. H = Σ (H_T · W_T)

D. H = I₀ · e^(-μx)

Explanation: The study materials state that the Equivalent Dose (H) is calculated by multiplying the absorbed dose by a radiation weighting factor (W_R), specifically H = D · W_R. The other options represent absorbed dose divided by W_R, the formula for Effective Dose, and the X-ray attenuation formula, respectively.

Question 5: The probability of stochastic effects increases with the radiation dose.

A. Yes

B. No

Explanation: Stochastic effects occur randomly, with the probability of occurrence increasing with dose, although the severity does not. There is no threshold dose for these effects.