The problem asks for the ratio of heating times of silver and gold. We are given that the crucibles are identical, the masses of silver and gold are equal, the final temperature is the same, and heat loss is negligible. The power of the furnaces is also the same, which means the rate of heat transfer is the same for both substances.
The amount of heat required to raise the temperature of a substance is given by the formula:
\[ Q = mc \Delta T \]
where:
The rate of heat transfer is given by P = Q / t, where P is the power and t is the time. Since the power of the furnaces is the same, we have:
\[ P = \frac{m_s c_s \Delta T}{t_s} = \frac{m_g c_g \Delta T}{t_g} \]
We are given that $$m_s = m_g$$ (equal masses) and $$\Delta T_s = \Delta T_g$$ (same temperature change). Therefore, we can simplify the equation to:
\[ \frac{c_s}{t_s} = \frac{c_g}{t_g} \]
We need to find the ratio $$t_s / t_g$$. Rearranging the equation, we get:
\[ \frac{t_s}{t_g} = \frac{c_s}{c_g} \]
Now, we need to find the specific heat capacities of silver and gold from the provided table. The table provides 'Удельная теплоемкость, Дж/(кг·°C)', which is the specific heat capacity.
From the table:
Now we can calculate the ratio of heating times:
\[ \frac{t_s}{t_g} = \frac{c_s}{c_g} = \frac{250}{130} \]
\[ \frac{t_s}{t_g} \approx 1.923 \]
Rounding the answer to the nearest tenth, we get 1.9.
| Металл | Плотность, кг/м³ | Удельная теплоемкость, Дж/(кг·°C) |
|---|---|---|
| алюминий | 2700 | 920 |
| железо | 7800 | 460 |
| золото | 19300 | 130 |
| медь | 8900 | 400 |
| олово | 7300 | 230 |
| свинец | 11300 | 140 |
| серебро | 10500 | 250 |
| цинк | 7100 | 400 |