To determine which substance would heat up the slowest when exposed to sunlight for the same amount of time, we need to compare their specific heats. The specific heat of a substance is a measure of how much energy is required to raise the temperature of a unit mass of the substance by one degree Celsius. A higher specific heat means that the substance can absorb more energy without a significant change in temperature.
Let's examine the specific heats provided for each substance:
- Brick: [tex]\( 0.9 \, \frac{J}{g \, ^\circ C} \)[/tex]
- Dry Soil: [tex]\( 1.26 \, \frac{J}{g \, ^\circ C} \)[/tex]
- Paper: [tex]\( 1.336 \, \frac{J}{g \, ^\circ C} \)[/tex]
- Water: [tex]\( 4.18 \, \frac{J}{g \, ^\circ C} \)[/tex]
By comparing these values, we identify the substance with the highest specific heat, since it will absorb more energy before increasing in temperature, thus heating up the slowest.
- Brick: [tex]\( 0.9 \)[/tex]
- Dry Soil: [tex]\( 1.26 \)[/tex]
- Paper: [tex]\( 1.336 \)[/tex]
- Water: [tex]\( 4.18 \)[/tex]
Clearly, water has the highest specific heat value of [tex]\( 4.18 \, \frac{J}{g \, ^\circ C} \)[/tex]. Hence, water will heat up the slowest when all four substances are exposed to the same conditions.
Therefore, the correct answer is:
A. Water
