Five metal samples, with equal masses, are heated to 200oC. Each solid is dropped into a beaker containing 200 ml 15oC water. Wh

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Five metal samples, with equal masses, are heated to 200oC. Each solid is dropped into a beaker containing 200 ml 15oC water. Wh

ich metal will cool the fastest? A) aluminum B) copper C) gold D) platinu Which sample of copper would demonstrate the GREATEST increase in temperature if 500 J of energy were added to the sample? A) 0.5 kg B) 1.0 kg C) 1.5 kg D) 2.0 kg Eliminate

Physics

1 answer:

ValentinkaMS [3.4K] · Answer 1 · 2026-03-21T09:39:27+03:00

Part 1) Which metal will cool the fastest?
To determine this, we need to consider the heat flow rate formula, which indicates the speed at which a substance can gain or lose heat:
$\frac{\Delta Q}{\Delta t} = -k \frac{A \Delta T}{x}$
where:
$\Delta Q$ denotes the heat exchanged
$\Delta t$ indicates the duration
k represents the thermal conductivity of the material
A is the area over which heat transfer takes place
$\Delta T$ shows the change in temperature
x is the thickness of the substance
It is evident that the heat flow rate $\frac{\Delta Q}{\Delta t}$ is directly related to k, the thermal conductivity. Thus, a higher value of k means that the metal will cool more quickly.
Upon examining the thermal conductivity values for each metal, we observe:
- Aluminium: 237 W/(mK)
- Copper: 401 W/(mK)
- Gold: 314 W/(mK)
- Platinum: 69 W/(mK)
Consequently, copper has the highest heat flow rate, making it the metal that cools the fastest.

Part 2) Which sample of copper demonstrates the greatest increase in temperature
To address this part, we can examine how the heat exchanged Q correlates with temperature increase $\Delta T$ :
$Q=m C_S \Delta T$
where m indicates the mass and Cs represents the specific heat capacity of the material. By rearranging the equation, we derive
$\Delta T= \frac{Q}{m C_s}$
As a result, it becomes clear that the temperature increase is inversely related to the mass m. Thus, the block exhibiting the highest temperature rise will be the one with the least mass, hence the right choice is A) 0.5 kg.