Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The dose of X-rays and most other ionizing radiations is measured as Roentgen units. Reason (R): One Roentgen is that dose of radiation, which produces one electrostatic unit of charge in one cm3 volume under a standard set of conditions. In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Remember that Roentgen is an obsolete unit, and modern measurements use Sievert.

Answer 1

The Correct Option is B

Step 1: Concept
Units of measurement for ionizing radiation

Step 2: Meaning
Understanding the units used to measure ionizing radiation and their definitions.

Step 3: Analysis
Assertion (A) states that the dose of X-rays and most other ionizing radiations is measured in Roentgen units. This is incorrect, as the current international standard unit for measuring exposure to ionizing radiation is the Sievert (Sv), not Roentgen (R). Reason (R) provides a definition of one Roentgen, which is accurate but irrelevant since the assertion about the unit used is outdated.

Step 4: Conclusion
The assertion is incorrect due to the change in standard units for measuring ionizing radiation. The reason provides historical information that does not address the current measurement standards. Final Answer: (B)