## Grade 9 Natural Science: Multiple-Choice Questions

### The primary energy source used in Eskom power plants is….

• A natural gas.Â
• B uranium.Â
• C coal.Â
• D oil.Â

• A 2Â
• B 3Â
• C 4Â
• D 5Â

### Which one of the following groups of sources of energy is sustainable and has a very small negative impact on the environment?Â

• A Sun-heated steam, waves in the sea and wind.Â
• B Coal, nuclear fuel and wind.Â
• C Earth oil, hydroelectric power and wave power.Â
• D Solar energy, coal and falling water.Â

### â€¦ may cause burns, cancer and gene mutation if the skin is exposedÂ to it due to its radioactive nature.Â

• A CoalÂ
• B Falling waterÂ
• C SteamÂ
• D Nuclear wasteÂ

## Grade 9 Electric Circuits Questions

Study circuits A, B, C and D and answer questions. All bulbs and cells are identical.Â

• Which circuit has the highest resistance? (1)Â Answer: D
• In circuit B, what is the component that is circled? (1)Â Answer: BatteryÂ
• What is the purpose of the component circled? (1)Â Answer: It is a source of (electrical) energy.
• What is the voltage of each bulb in circuit D? (2)Â Answer: 1,5 Ã· 3 = 0,5 V
• In which circuit will the bulb/bulbs be the brightest? (1)Answer: Â B

Mention factors that can influence the resistance of a resistor.Â

• Temperature of the resistor.Â
• Type of a resistor.Â
• Thickness of the resistor.Â
• Length of the resistor.Â

Study the circuit diagram below and answer the questions that follow. Each cell has a potential difference of 1,5 V. The resistance of bulb S is R and the resistance of bulb T is 4R.Â

• In which way are bulbs S and T connected? (1)Â Answer: ParallelÂ
• What is the reading on voltmeter V1? (2)Â Answer: V1 = 3 x 1,5= 4,5 VÂ