To produce 18 mAs at 300 mA, what exposure time should be selected?

To determine the exposure time needed to produce 18 mAs (milliampere-seconds) at a current of 300 mA (milliamperes), you can use the formula for calculating mAs:

[ \text{mAs} = \text{mA} \times \text{time (s)} ]

Rearranging the formula to solve for time yields:

[ \text{time (s)} = \frac{\text{mAs}}{\text{mA}} ]

Substituting the given values:

[ \text{time (s)} = \frac{18 , \text{mAs}}{300 , \text{mA}} ]

Calculating this gives:

[ \text{time (s)} = \frac{18}{300} = 0.06 , \text{s} ]

To convert this to milliseconds, remember that 1 second equals 1000 milliseconds:

[ 0.06 , \text{s} = 60 , \text{ms} ]

Thus, the correct exposure time to produce 18 mAs at 300 mA is 60 ms. This aligns with the choice given, making it