What does an impact test measure?

An impact test is designed specifically to measure toughness and impact resistance of materials. Toughness refers to a material's ability to absorb energy and plastically deform without fracturing, which is particularly important in applications where materials may face sudden forces or impacts. The test typically involves striking a specimen with a hammer or pendulum and observing how much energy it absorbs before breaking.

This property is crucial, as materials used in construction, manufacturing, or any applications subject to dynamic loading need to withstand sudden shocks or impacts without failing. Hence, a high toughness value indicates a material that can resist abrupt loads very well, making option B the correct choice.

The other options refer to different properties: tensile strength measures how much force a material can withstand while being stretched, thermal conductivity assesses how well a material conducts heat, and corrosion resistance determines a material’s ability to withstand corrosion. These are important mechanical and physical properties, but they are not the focus of an impact test.