Question

A paper strip is rolled and punched by a triangular punch. After unrolling, what pattern of holes would appear on the strip?

• A. A
• B. B
• C. C
• D. D

Hint:

When a coiled strip is punched, unrolling produces a linear repetition of the punched shape, identical in orientation and equally spaced.

Answer 1

The Correct Option is C

Step 1: Understand the punching process.
The strip is rolled into a cylinder. When a triangular punch is pressed through the side of the roll, it penetrates all the layers of the spiral.
Step 2: Effect of unrolling.
After unrolling, each punched layer leaves a hole at regular intervals along the length of the strip. Since the strip was coiled evenly, the punched triangles appear repeated periodically down the length.
Step 3: Orientation of triangles.
All triangular holes will face the same direction, because the punch orientation does not change as it pierces through.
Step 4: Compare with options.
- (A): Shows alternating orientations—incorrect.
- (B): Shows varying sizes/orientations—incorrect.
- (C): Shows evenly spaced identical triangles, matching the rolled punching process.
- (D): Shows misaligned orientation—incorrect.
Final Answer: \[ \boxed{\text{C}} \]