Question

Common Causes of Errors in using a PD ruler: The subject may not look directly at the measurer's ___ during the test.

A) Hand
B) Pupil
C) Forehead
D) Shoulder

Answer 1

The common causes of errors in using a PD ruler include limitations of the measuring device, the skill of the person making the measurement, and irregularities in the object being measured.

Step-by-step explanation:

The common causes of errors in using a PD ruler are:

1. Limitations of the measuring device: The smallest division on the ruler, such as 0.1 in., can lead to inaccuracies in measurements.
2. The skill of the person making the measurement: If the person using the ruler has bad eyesight or lacks experience in making precise measurements, it can result in errors.
3. Irregularities in the object being measured: For example, if one side of the paper is slightly longer than the other, it can introduce uncertainty in the measurements.

It is important to consider all these factors and their possible effects when using a PD ruler to minimize errors and ensure accurate measurements.