Question

If a teacher is on the dias 30 feet away from the last row of the students, what should be the height of every letter teacher writes on the blackboard?

• A. At least 1.5 to 2 inches
• B. At least 2 to 4 inches
• C. At least 0.5 to 1 inches
• D. At least 3 to 3.5 inches

Hint:

Exam Tip:
General Rule: For every 10 feet of viewing distance, the letter height should be at least 0.5 to 1 inch.
For 30 feet: 1.5 to 3 inches.
For optimal readability, use bold and clear letters, and ensure good contrast between the writing and the board.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
This question tests knowledge of the principles of visual aids and classroom communication, specifically the recommended size of letters on a blackboard for optimal visibility.

Step 2: Key Formula or Approach:
A general rule of thumb in education and visual communication is that for every 10 feet of distance, the letter height should be at least 0.5 inches.
However, a more commonly used rule is the "1 inch per 10 feet" rule for readability.
Given that the teacher is 30 feet away from the last row:
Using the rule of thumb:
\[ \text{Letter Height} = \frac{\text{Distance}}{20} \text{ to } \frac{\text{Distance}}{15} \] For 30 feet:
Minimum height = \(30/20 = 1.5\) inches.
Recommended height = \(30/15 = 2\) inches.
Therefore, the letter height should be at least 1.5 to 2 inches.

Step 3: Analyzing the Options:

• (A) At least 1.5 to 2 inches: This matches the calculated recommendation.
• (B) At least 2 to 4 inches: Too large for a blackboard; this would be for very large posters or billboards.
• (C) At least 0.5 to 1 inches: Too small; students at the back would not be able to read clearly.
• (D) At least 3 to 3.5 inches: Too large and impractical for a blackboard.

Step 4: Final Answer:
The height of every letter should be at least 1.5 to 2 inches. Therefore, option (A) is correct.