Why use a pencil in multiple-choice tests?

According to TodayIFoundOut, today's testing machines use image sensors and complex image processing algorithms.

These algorithms will select the location marked the most bold and it is based on that to assign the tester's answer. Therefore, the competitor should highlight and fill the entire area of ​​a circle for the selected answer, if marking V or X, the dot machine may incorrectly identify.

Pencils are preferred because you can easily erase your choices earlier.

Older models have a simpler structure. The device will project a beam of light onto the included document, and discover special signs (with pencil marks) . At those signs less light is reflected back from them than from the paper with no sign. The marking machines then record the less reflective part of the light than the answer.

As such, you can use pens, pencils and even pens using printer ink to take the test. However, pencil is preferred because you can easily erase your choice earlier. In addition, pencils are also a good choice because lead molecules form small, less mapped carbon sheets and almost "swallow" light when exposed. Black ink of ballpoint pen, fountain pen is not strong enough to use old marking machine systems.

There are many types of pencils and are distinguished according to the density, according to the material that makes the pen, sometimes the pen design. On the pen body, there are symbols such as HB, 2B, 3B . that are only the hardness and black of the pencil. H stands for Hard (hard lead), B for Black (soft lead), and F for Fine (neutral type, very rare).

Boldness of popular pencils.

The harder the pencil (the highest H is 9), the higher the lightness. In contrast, the softer the pencil, the darker the color. The pencil from 6B - 9B can help the contestant round out the fastest answer option when taking the multiple-choice exam. However, because lead is too bold, when it is necessary to replace the plan, it will be very difficult to clean up the circle. And if the eraser is still clean, there is still a blur, the dot marking machine will skip, not marking sentences with two rounds.

Whereas lead type B is easier to erase, for example, someone "accidentally" rubbed by hand is also enough to fly a mark made of lead B. Therefore, pencil 2B - 4B is chosen by It just gives good density, and is also hard to blur during the transport of the test.