There is a single electric bulb in a house of 100W power. This bulb is connected with 220 V power supply. What is the current passes through this bulb? If this blub glow 6 hours per day then find the amount of energy spend by in one month of 30 days. Calculate the electricity bill of the house of the month if 1kWh=3600000 j =1 unit and cost of one unit electricity is Rs 10 rupees.
Answers
Answer: Electric power (P) is simply the product of current times voltage. Power has familiar units of watts. Since the SI unit for potential energy (PE) is the joule, power has units of joules per second, or watts. Thus, 1 A ⋅V= 1 W. For example, cars often have one or more auxiliary power outlets with which you can charge a cell phone or other electronic devices. These outlets may be rated at 20 A, so that the circuit can deliver a maximum power P = IV = (20 A)(12 V) = 240 W. In some applications, electric power may be expressed as volt-amperes or even kilovolt-amperes (1 kA ⋅V = 1 kW). To see the relationship of power to resistance, we combine Ohm’s law with P = IV. Substituting I = V/R gives P = (V/R)V=V2/R. Similarly, substituting V = IR gives P = I(IR) = I2R. Three expressions for electric power are listed together here for convenience:
Explanation: