Final answer:
The units milliampere-seconds (mAs) and milliampere-minutes (mA-min) refer to radiation dosage over time, whereas milliampere-days (mA-d) is not a standard unit. For electric current, milliamperes (mA) are used for small currents, whereas amperes (A) are the standard unit, both calculated based on the charge flowing over a certain time.
Step-by-step explanation:
The units used to specify the exposure in terms of milliampere-seconds (mAs) per week or milliampere-minutes (mA-min) per week are measurements of radiation dosage delivered over time. Although not standard, hypothetically, if one were to measure exposure over a week, milliampere-days (mA-d) could be a unit created for such purpose. However, the standard units for exposure in radiology or radiation protection are often coulombs per kilogram (C/kg) for electric charge exposure or sieverts (Sv) and millisieverts (mSv) for radiation dose.
When it comes to calculating electric current, it's important to understand that an ampere (A) is the unit of electric current in the International System of Units (SI). For smaller currents, milliamperes (mA) is commonly used, where 1 mA is equal to one-thousandth of an ampere.
For instance, example problems might involve calculations such as finding the current produced by solar cells of a pocket calculator when a certain charge passes through in a given time, determining average current in other applications or understanding the flow of static charge. All of these situations require a clear understanding of the concepts of electric current (measured in amperes) and how to calculate it given charge and time.