. Charlie is measuring a piece of equipment that he is using in an electrical repair. The true length of the piece is 3.749 cm. Charlie is using a device marked in half-millimetres. What measurement and uncertainty will he record? Calculate in detail

Answer 1

To measure the true length of 3.749 cm using a device marked in half-millimeters, Charlie will record a measurement and uncertainty as follows:

1. Measurement:
- The closest half-millimeter measurement below 3.749 cm would be 3.75 cm.
- The closest half-millimeter measurement above 3.749 cm would be 3.75 cm.
- Therefore, Charlie will record the measurement as 3.75 cm.

2. Uncertainty:
- The uncertainty is half of the smallest division on the device, which is half a millimeter or 0.5 mm.
- To convert this uncertainty to centimeters, we divide by 10 (since there are 10 millimeters in a centimeter): 0.5 mm ÷ 10 = 0.05 cm.
- Therefore, Charlie will record the uncertainty as ±0.05 cm.

Therefore, Charlie will record the measurement as 3.75 cm ± 0.05 cm.