Smart materials are best described as materials whose properties change in response to external stimuli.

Smart materials are best described as materials whose properties change in response to external stimuli.

• A. They are inert
• B. They change in response to external stimuli
• C. They are cheap
• D. They decompose quickly

Answer: (B)

Smart materials are materials whose properties can change in response to external stimuli. This means they actively respond to things like temperature, electric or magnetic fields, light, or mechanical stress, by altering characteristics such as shape, stiffness, color, or electrical properties. That direct ability to adjust their behavior when something in the environment changes is what defines them. For example, shape memory alloys bend or return to a pre-set shape with a change in temperature, electrochromic materials change color when an electric signal is applied, and piezoelectric materials alter their stiffness or generate a voltage under stress. The other ideas don’t describe smart materials as a class. Being inert means not reacting at all, which is the opposite of the responsive behavior smart materials exhibit. Being cheap is about cost, not functional behavior. Decomposing quickly would be a drawback for most smart material applications and doesn’t define their functional principle.

Smart materials are materials whose properties can change in response to external stimuli. This means they actively respond to things like temperature, electric or magnetic fields, light, or mechanical stress, by altering characteristics such as shape, stiffness, color, or electrical properties. That direct ability to adjust their behavior when something in the environment changes is what defines them. For example, shape memory alloys bend or return to a pre-set shape with a change in temperature, electrochromic materials change color when an electric signal is applied, and piezoelectric materials alter their stiffness or generate a voltage under stress.

The other ideas don’t describe smart materials as a class. Being inert means not reacting at all, which is the opposite of the responsive behavior smart materials exhibit. Being cheap is about cost, not functional behavior. Decomposing quickly would be a drawback for most smart material applications and doesn’t define their functional principle.