10_klass_tasks for lesson

Problem solving

Task 1. There is an electric lamp, designed for a current of 100 watts. The lamp is lit daily for 6 hours. In the office of 30 lamps. Find the current work for one month (30 days) and the cost of energy consumed at a tariff of 8.43 tenge per 1 kWh.

Task 2. There is an electric lamp, designed for a current of 100 watts. The lamp is lit daily for 6 hours. In the office of 30 lamps. The school has 50 classrooms. Find current work for one month (30 days) and the cost of energy consumed at a rate of 13.64 tenge per 1 kWh.

Task 3. There is an electric stove, designed for a current capacity of 10,000 watts. Daily working for 10 hours. In the dining room 4 plates. Find current work for one month (30 days) and the cost of energy consumed at a rate of 13.64 tenge per 1 kWh.

Task 4. In the office of computer science 15 computers with a capacity of 800 watts, which operate for 5.5 hours per day. What is the power consumption for 24 working days? The cost of electricity for the period at a cost of 13.64 tenge / kW · h.

Task 5. Iron power 1200 watts. Calculate the current work for 15 minutes of work. Translate the resulting value in kWh. Calculate how much you will pay for using this iron for 15 minutes of continuous operation at a rate of 11 tenge 53 tiyn.

Task 6. In the household electric cooker, designed for a voltage of 220 V, there are two spirals, the resistance of each of which in the operating mode is 80.7 Ohms. With the help of a switch, one helix, two helixs in series or two helixes in parallel can be included in the network. Find power in each case.

Task 7. Explain why, when two lamps of 40 and 100 W are switched on in series, the first one burns much brighter than the second.