Polystyrene is a light, transparent, thermoplastic. Which of the following is a common application consistent with its properties and processing?

Introduction / Context:
Matching polymer properties to applications is a core skill in materials engineering. Polystyrene (PS) is rigid, transparent, easy to mould, and economical, making it suitable for consumer goods requiring shape stability and surface finish.

Given Data / Assumptions:

• PS is amorphous, with good clarity and stiffness but relatively low toughness.
• It processes well by injection moulding.
• We seek the application that best fits these traits.

Concept / Approach:
PS’s clarity and mouldability lend themselves to products like toys, combs, disposable cutlery, and housings. For thin films such as flexible packaging bags, polyethylene (LDPE/LLDPE) dominates due to superior toughness and flexibility. Non-stick cookware surfaces require PTFE (Teflon), not PS. High-voltage cable insulation is typically crosslinked polyethylene (XLPE) or specialised polymers with better dielectric strength and thermal resistance than PS can provide in that service.

Step-by-Step Solution:
Compare application demands with PS traits.Injection-moulded consumer items like toys/combs align well.Eliminate film packaging, non-stick coatings, and HV insulation as mismatches.

Verification / Alternative check:
Product catalogues and polymer handbooks list PS for rigid consumer goods; PE for films; PTFE for non-stick; XLPE for power cables.

Why Other Options Are Wrong:
Packaging bags: usually LDPE/LLDPE due to flexibility and toughness.Non-stick surfaces: PTFE, not PS.High-voltage insulation: materials with higher dielectric/thermal performance than PS.

Common Pitfalls:
Assuming any transparent plastic suits films or cookware without considering toughness and thermal stability.

Final Answer:
Toys and combs