This physics problem tests your understanding of fundamental physical laws and their applications. The step-by-step solution below breaks down the problem using relevant equations and physical reasoning.
ScanSolve AI Answer
Here are the solutions to your problems. 1. Step 1: Calculate the daily energy consumption of the hi-fi set. The power is 40 W and it plays for 8 hours a day. E_daily = P × t_daily E_daily = 40 W × 8 h = 320 Wh Step 2: Calculate the monthly energy consumption. For a month of 31 days: E_monthly = E_daily × 31 days E_monthly = 320 Wh/day × 31 days = 9920 Wh Step 3: Convert the monthly energy consumption to kilowatt-hours (kWh). E_monthly, kWh = 9920 Wh1000 Wh/kWh = 9.92 kWh Step 4: Calculate the total cost. The cost is M0.80 per kWh. Cost = E_monthly, kWh × Cost per kWh Cost = 9.92 kWh × M0.80/kWh Cost = M7.936 The cost of playing the hi-fi for a month is M7.94. 2. a) The different cooking elements (oven and hot plates) are likely connected in parallel. This is because connecting them in parallel ensures that each element receives the full 240 V mains supply, allowing them to operate independently at their rated power. If they were in series, the voltage would divide, and they would not function correctly or efficiently. b) Step 1: Calculate the total power of all cooking elements when they are on. Oven power P_oven = 3000 W. Each hot plate power P_plate = 1000 W. There are two hot plates. P_total = P_oven + 2 × P_plate P_total = 3000 W + 2 × 1000 W P_total = 3000 W + 2000 W = 5000 W Step 2: Calculate the total current drawn by the stove. Using the formula P = V × I, we can find the current I = (P)/(V). I = 5000 W240 V I ≈ 20.83 A Step 3: Determine a suitable fuse value. A fuse should have a rating slightly higher than the maximum operating current to prevent it from blowing unnecessarily, but low enough to protect the circuit from overcurrent. Standard fuse ratings often include 5 A, 13 A, 30 A. Since 20.83 A is the operating current, a 30 A fuse would be suitable. The value of a suitable fuse is 30 A. c) Step 1: Identify the total power and convert the operating time to hours. Total power P_total = 5000 W (from part b). Operating time t = 50 minutes. t = (50)/(60) hours = (5)/(6) hours Step 2: Calculate the energy consumed in kilowatt-hours (kWh). E = P_total × t E = 5000 W × (5)/(6) h E = (25000)/(6) Wh ≈ 4166.67 Wh E_kWh = 4166.67 Wh1000 Wh/kWh ≈ 4.1667 kWh Step 3: Calculate the total cost. The cost is M0.80 per kWh. Cost = E_kWh × Cost per kWh Cost = 4.1667 kWh × M0.80/kWh Cost ≈ M3.33336 The cost of operating all three cooking elements for 50 minutes is M3.33. 3 done, 2 left today. You're making progress.