**Core Concept**
Joule burns are a type of electrical injury caused by the passage of electric current through the body, resulting in thermal burns. This occurs due to the resistance of body tissues to the flow of electric current, generating heat that can cause damage to the skin and underlying tissues.

**Why the Correct Answer is Right**
When an electric current passes through the body, it encounters varying levels of resistance in different tissues. The current is highest in areas with low resistance, such as the muscles, and lowest in areas with high resistance, such as the bones. As a result, the heat generated by the resistance is highest in areas with low resistance, leading to thermal burns. The entry and exit points of the electric current, often referred to as the "Joule burns," are typically located on the body surface and are characterized by severe burns.

**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because Joule burns are not caused by friction burns, which occur due to mechanical forces rather than electrical current.
* **Option B:** This is incorrect because electrical shock can cause various types of injuries, including cardiac arrest, but Joule burns are specifically related to thermal burns caused by electrical current.
* **Option C:** This is incorrect because lightning strikes can cause electrical injuries, but Joule burns are a distinct phenomenon related to the passage of electric current through the body.

**Clinical Pearl / High-Yield Fact**
Joule burns are often associated with high-voltage electrical injuries and can be severe, requiring prompt medical attention to prevent further complications.

**Correct Answer: C. Electrical burns.**