Answer :
If the temperature of the heat source is increased, the efficiency of a Carnot engine will **increase**.
Here's why:
* **Carnot Efficiency:** The efficiency of a Carnot engine is given by:
```
Efficiency = 1 - (T_c / T_h)
```
where:
* T_c is the temperature of the cold reservoir (sink) in Kelvin.
* T_h is the temperature of the hot reservoir (source) in Kelvin.
* **Relationship between Temperature and Efficiency:** As you can see from the formula, the efficiency is directly related to the ratio of the cold reservoir temperature to the hot reservoir temperature. When the temperature of the hot reservoir (T_h) increases, the ratio (T_c / T_h) decreases. This leads to an increase in the value of (1 - (T_c / T_h)), which is the efficiency of the engine.
**In simpler terms:** Increasing the temperature difference between the hot and cold reservoirs makes the engine more efficient at converting heat energy into useful work.
**Important Note:** This assumes that the temperature of the cold reservoir remains constant. If the cold reservoir temperature also increases, the overall effect on efficiency depends on the relative change in both temperatures.