NECO Physics
Past Questions

AI Explanation

**The reasoning** A conductor is a material that allows electric current (the flow of electrons) to pass through it easily. Metals like **iron** have free electrons in their atomic structure that can move around freely. When you apply a voltage, these electrons flow from one point to another, creating current. **Iron** (option C) is a metal, so it's packed with these mobile electrons. That's why it conducts electricity brilliantly — think of wires, electrical poles, and metal tools. **Why the wrong options tempt you** Wood, rubber, and plastic are **insulators** — they hold their electrons tightly, preventing flow. The trap? In everyday life, you see plastic coating wires or rubber gloves protecting electricians. You might think "electricity-related = conductor," but actually they're used *because* they **don't** conduct! They keep you safe by blocking the current. **Quick takeaway** **Metals conduct; non-metals (like wood, rubber, plastic) insulate.** If it's shiny and metallic, electrons can dance through it freely!

AI Explanation

**The reasoning** The metric system works in powers of 10, and the prefix "kilo-" always means **1000 times** the base unit. So: - 1 kilometre = 1000 metres - 1 kilogram = 1000 grams - 1 kilolitre = 1000 litres Think of it this way: when you walk from your house to the main road (maybe 500 metres), you've covered half a kilometre. To complete 1 full kilometre, you'd need to walk that distance twice — which equals 1000 metres total. The conversion is straightforward: **1 km = 1000 m** **Why the wrong options tempt you** - **10 (A)** — You might confuse "kilo" with "deca" (which means 10) - **100 (B)** — You might think of "hecto" (which means 100) or mix up different metric conversions - **10000 (D)** — This looks like "kilo" because of all the zeros, but it's actually 10 kilometres, not 1 **Quick takeaway** Remember: **"Kilo" = 1000** — whether it's kilometres, kilograms, or kilowatts, the prefix always multiplies by 1000.

AI Explanation

**The reasoning** When you release an object and it falls toward the ground, there's only one force pulling it downward: **gravity**. This is Earth's gravitational force acting on the object's mass. Free fall means the object is falling *without* any support or propulsion — just responding to gravity's pull. The acceleration is constant at approximately **g = 10 m/s²** (or more precisely 9.8 m/s²). This means every second, the object's velocity increases by 10 m/s downward. Whether it's a stone, book, or mango falling from a tree — gravity is the sole cause of that downward acceleration. **Why the wrong options tempt you** - **Wind** can push objects sideways or slow them down, but doesn't cause the *downward* acceleration - **Friction** (air resistance) actually *opposes* motion and slows falling objects — it doesn't accelerate them - **Magnetism** only affects magnetic materials like iron — it won't pull a stone or paper downward **Quick takeaway** Gravity is the universal force that pulls all objects toward Earth's center — it's the *only* reason things accelerate downward when falling freely.