Question

Think about the helical coil of a telephone cord or a spiral binding. Suppose that you view the spiral from one end and find that it is a left-handed twist. If you view the same spiral from the other end, is it a right-handed or left- handed twist?

Short answer

Answer: When viewed from the other end, the same helical coil will appear to have a right-handed twist due to the change in perspective.

Step-by-step solution

Handedness of a helical coil

A helical coil has a handedness (left or right-handed twist) that describes the direction it spirals. Left-handed helix means the direction of the helix turns from the top-right to the bottom-left, while a right-handed helix turns from the top-left to the bottom-right.

Observation from one end

When we view the helical coil from one end and observe a left-handed twist, it means the spiral goes away from us in a counterclockwise direction.

Observation from the other end

To determine the handedness when viewing the same helical coil from the other end, imagine looking through the coil in the opposite direction (turning around or flipping the coil).

Conclusion

When you view the same left-handed helical coil from the opposite end, it appears as a right-handed twist. This is due to the change in perspective that reverses the apparent direction of the helix.