Power consumed (P) = I²R = (2 A)² 200 Ω = 4 200 = 800 W = 0.8 kW. Total energy consumed (E_total) = Power Time = 0.8 kW 10 h = 8 kWh. Total cost of electricity = E_total Rate = 8 kWh ₹5/kWh = ₹40. Energy converted into light kWh. Cost spent on producing light = E_light Rate = 1.6 kWh ₹5/kWh = ₹8.
An incandescent electric bulb converts 20% of its power consumption into light, and the remaining power is dissipated as heat. The bulb's filament has a resistance of 200 Ω and 2 A current flows through it. If the bulb remains ON for 10 h and the rate of electricity charge is ₹5/ unit, then which among the following is the correct amount for the money spent on producing light ?
Asked in UPSC NDA 2 2024 · Topic: Electric Current (Electrical Power and Energy, Joule heating effect)
More Physics questions
- Fuse is the most important safety device used for protecting the circuits due to :
- Electric generator is a device which converts _____ energy into _____ energy.
- Fuse wire of appropriate thickness improves its efficiency to prevent damage. These wires are made up of :
- The approximate life time of a common electric bulb is 1,000 hrs whereas the approximate life time of a LED bulb is :
- A fuse is a :
- Electrical energy is converted into mechanical energy in :
- What is the difference between a CFL and an LED lamp ? Consider the following statements: To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semiconductor material. The average life span of a CFL is much longer than that of an LED lamp. A CFL is less energy-efficient as compared to an LED lamp. Which of the statements given above is/are correct ?
- Five bulbs each of 100 watt capacity in a tunnel are illuminated continuously for twenty hours. The consumption of electricity will be: