Physics 2012 JAMB Past Questions - Question 2: In order to remove the error of parallax when taking measurement with a meter rule ,the eye should be focused

Correct Answer

C

Explanation

Placing the eye vertically on the markings ensures that the point is not laterally displacedTo remove the error of parallax when taking measurements with a meter rule (or any other measuring instrument), you should ensure that your eye is focused directly in line with the measurement you are taking. Parallax occurs when the position of the observer's eye is not in line with the scale of the measuring instrument. This can lead to a visual error in the reading.

Here's how you can focus your eye to minimize parallax error:

1. Place the meter rule (or measuring instrument) on a flat and stable surface.
2. Stand or position yourself so that you are directly in front of the measurement you want to take.
3. Align your eye so that it is at the same level as the point on the scale you are measuring.
4. Ensure that your eye is at a 90-degree angle to the scale, meaning that it is neither above nor below the scale but on the same plane as the measurement.

By doing this, you eliminate the parallax error because your line of sight is parallel to the scale, and you are looking at it from the correct angle. This ensures a more accurate measurement.

It's important to note that the parallax error can be significant when taking precise measurements, so taking care to eliminate it is essential for accurate results.