Which of the following objects is not a conductor of electricity?

Step 1: Analyze the question We need to find the object that does not conduct electricity, which means an insulator.

Step 2: The concept

• Conductors have free charge carriers (free electrons or ions) that move easily when a voltage is applied. Examples: metals, graphite, salt solutions, and the Earth (moist soil contains ions in water).
• Insulators have very few free charge carriers, so they resist current flow. Examples: dry wood, rubber, plastic, glass, dry paper.

Step 3: Check each option

• A. The Earth: Conducts electricity. Moist soil and minerals allow current to flow, which is why we "earth" or ground electrical appliances to discharge current safely.
• B. Human body: Conducts electricity. The body contains water with dissolved salts (ions), which is why electric shock is dangerous.
• C. Iron rod: Conducts electricity. It is a metal with many free electrons.
• D. Dry wood: Does not conduct electricity. It has almost no free electrons, so it is an insulator.

Step 4: Answer The object that is not a conductor is dry wood, option D.

Tip: Remember the word "dry". Dry wood is an insulator, but wet wood can conduct a little because the water contains ions. In exams, if you see rubber, plastic, glass, dry wood, or dry paper, think "insulator." If you see metals, the Earth, or the human body, think "conductor."