Multiple choice

Directions: For this question, select the best of the answer choices given.

An experimental microwave clothes dryer heats neither air nor cloth. Rather, it heats water on clothes, thereby saving electricity and protecting delicate fibers by operating at a lower temperature. Microwaves are waves that usually heat metal objects, but developers of a microwave dryer are perfecting a process that will prevent thin metal objects such as hairpins from heating up and burning clothes. Which of the following, if true, most strongly indicates that the process, when perfected, will be insufficient to make the dryer readily marketable?

  1. Metal snap fasteners on clothes that are commonly put into drying machines are about the same thickness as most hairpins.

  2. Many clothes that are currently placed into mechanical dryers are not placed there along with hairpins or other thin metal objects.

  3. The experimental microwave dryer uses more electricity than future, improved models would be expected to use.

  4. Drying clothes with the process would not cause more shrinkage than the currently used mechanical drying process causes.

  5. Many clothes that are frequently machine-dried by prospective customers incorporate thick metal parts such as decorative brass studs or buttons.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The argument assumes that preventing hairpins from heating will solve the metal heating problem. Option E weakens this by showing that many clothes have thick metal parts (studs, buttons) that would still heat up in a microwave dryer. Even if thin metal objects don't heat, thick metal parts still would, making the dryer unsafe for most commercially machine-dried clothes.

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