6A Physics Electricity CW 2023 Date due: 09/10/2023 Name: Jaden Small Class: Physics-1 Instructions: Submit this assignment on folder/typing paper before or on the due date. Marks will be deducted for late work. 1. a) Write Kirchhoff’s laws and state the physical basis of each [4 marks] Kirchoff’s first law states that the total current flowing into a node is equal to the total current flowing out of that node. This law is based on the law of conservation of charge. Kirchoff’s second law states that the total EMF is equal to the sum of all the potential differences across all the resistances in the loop. This law is based on the law of conservation of energy. b) i) Find the branch currents flowing in the circuit below [6 marks] 60 = 10𝐼3 + 30𝐼2 60 = 10𝐼1 + 10𝐼2 + 30𝐼2 60 = 10𝐼1 + 40𝐼2 120 + 60 = 10𝐼3 + 20𝐼1 180 = 10𝐼1 + 10𝐼2 + 20𝐼1 180 = 30𝐼1 + 10𝐼2 60 = 10𝐼1 + 40𝐼2 −(180 = 30𝐼1 + 10𝐼2 ) × 4 6A Physics Electricity CW 2023 60 = 10𝐼1 + 40𝐼2 −(720 = 120𝐼1 + 40𝐼2 ) −660 = −110𝐼1 −660 𝐼1 = −110 𝐼1 = 6𝐴 180 = 30(6) + 10𝐼2 180 = 180 + 10𝐼2 0 = 10𝐼2 𝐼2 = 0𝐴 𝐼3 = 𝐼1 + 𝐼2 𝐼3 = 6 + 0 = 6𝐴 ii) Find the potential difference between A and B. [3 marks] 𝑉𝐴𝐵 = 60 + 10𝐼3 𝑉𝐴𝐵 = 60 + 10 × 6 𝑉𝐴𝐵 = 60 + 60 = 120𝑉 Date due: 09/10/2023 6A Physics Electricity CW 2023 2. (i) 1 1 1 = + 𝑅3,4 4 3 1 3 4 7 = + = 𝑅3,4 12 12 12 1 7 = 𝑅3,4 12 12 𝑅3,4 = 7 1 1 7 + 𝑅5,3,4 5 12 1 12 35 = + 𝑅5,3,4 60 60 1 47 = 𝑅5,3,4 60 60 𝑅5,3,4 = 47 = 𝑅𝑒𝑞 = 5 + 𝑅𝑒𝑞 = 60 47 235 60 295 + = 𝑜𝑟 6.28Ω 47 47 47 Date due: 09/10/2023 6A Physics Electricity CW 2023 (ii) 6 295 47 + 1 47 𝐼= = 0.82𝐴 57 𝐼= (iii) 47 ×5 57 235 𝑉5 = = 4.1𝑉 57 𝑉5 = 235 47 20 𝑉5(2𝑛𝑑) = 𝑉3 = 𝑉4 = 6 − ( + )= = 1.05𝑉 57 57 19 (iv) 235 47 𝐼5 = 57×5 = 57 = 0.82𝐴 20 4 𝑉5(2𝑛𝑑) = 19×5 = 19 = 0.21𝐴 20 20 20 5 𝑉3 = 19×3 = 57 = 0.35𝐴 𝑉4 = 19×4 = 19 = 0.26𝐴 Total: 25 marks Date due: 09/10/2023