QUESTION 7 A battery is made up of an unknown number of cells. Each of the cells in the battery is labelled 3V. The battery is connected in a circuit as shown. Ignore the resistance of the battery and the wires. Initially switch S, is open and the voltmeter connected across the ends of the battery reads 24V. 24V) V₂ V₁ 30 100 A 7.1 Does the reading of 24V represent emf or the terminal potential difference? Give a reason for your answer. (2) 7.2 Determine the number of cells in the battery? (1) When switch S, is now closed the ammeter A, reads 2A and V, reads 20V. 7.3 What will be the reading on: 7.3.1 V₁ € 7.3.2 V₂ (1) 7.4 What will the reading on A₂ be if 1,33A of current flows through the 32 resistor? (1) 7.5 How many coulombs of charge flows through A, in 1 second? (1) 7.6 Calculate the total resistance in the circuit. (4) 7.7 How long (in minutes) will it take 4 800J of electrical energy to flow through the 10 resistor? (5) 7.8 If switch S₂ is now opened (while S, remains closed) how will this affect the reading on Va? Explain. (4) (Choose from INCREASES, DECREASES or REMAINS THE SAME) [20] QUESTION 2 Si, water-ethanol, CuSO4, Fe₂O₂, cooking oil-iron fillings, Fe, Cl₂ 2.1. From above list identify the: 2.1.1. Heterogeneous mixture 2.1.2. Semi-metal. 2.1.3. Compound. 2.1.4. Rust. (1) 2.1.5. The substance that exists as a gas at room temperature. 33333 (1) (1) (1) (1) 2.2. Now, consider thoroughly stirred water-ethanol at room temperature. 2.2.1. Is this a homogeneous or heterogeneous mixture? (2) Explain the answer. 2.2.2. Name a suitable separation technique that can be used to separate (1) water-ethanol mixture 2.2.3. Name the physical property used in this technique mentioned in 2.2.2 (1) 2.2.4. Which component of the mixture will be left behind? 2.2.5. Why is this mixture considered miscible? 88@ (1) (2) QUESTION 2 2.1. Si, water-ethanol, CuSO4, Fe₂O₂, cooking oil-iron filings, Fe, Cl₂ From above list identify the: 2.1.1. Heterogeneous mixture 2.1.2. Semi-metal. 2.1.3. Compound. 2.1.4. Rust. (1) (1) (1) (1) 2.1.5. The substance that exists as a gas at room temperature. (1) 2.2. Now, consider thoroughly stirred water-ethanol at room temperature. 2.2.1. Is this a homogeneous or heterogeneous mixture? (2) Explain the answer. 2.2.2. Name a suitable separation technique that can be used to separate water-ethanol mixture (1) 33 2.2.3. Name the physical property used in this technique mentioned in 2.2.2 (1) 2.2.4. Which component of the mixture will be left behind? 2.2.5. Why is this mixture considered miscible? (1) (2) [12] QUESTION 3 3/6 The two graphs (not drawn to scale) below represent the change in temperature of two substances, X and Y, when heated for a certain time. Both substances were in the solid phase at 1-0 minutes. Substance Y Substance : Time (minutes) ... (2)