An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to a high temperature, by passing an electric current through it, until it glows with visible light (incandescence). The hot filament is protected from oxidation with a glass or quartz bulb that is filled with inert gas or evacuated. In a halogen lamp, filament evaporation is prevented by a chemical process that redeposits metal vapor onto the filament, extending its life. The light bulb is supplied with electric current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides mechanical support and electrical connections. 

Incandescent bulbs are much less efficient than most other types of electric lighting; incandescent bulbs convert less than 5% of the energy they use into visible light, with standard light bulbs averaging about 2.2%. The remaining energy is converted into heat. The luminous efficacy of a typical incandescent bulb is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some white LED lamps. Some applications of the incandescent bulb deliberately use the heat generated by the filament. Such applications include incubators, brooding boxes for poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, lava lamps, and the Easy-Bake Oven toy. Incandescent bulbs typically have short lifetimes compared with other types of lighting; around 1,000 hours for home light bulbs versus typically 10,000 hours for compact fluorescents and 30,000 hours for lighting LEDs. QUESTIONS:

Q1:
1. What is the main energy source for an incandescent bulb?
2. What is an incandescent bulb's energy source?
3. 
Q2:
1. Is the source for an incandescent bulb hot?
2. Is the filament in an incandescent bulb hot?
3. Does the source for an incandescent bulb get hot?
Q3:
1. How does the source for an incandescent bulb become hot?
2. How is the filament in an incandescent bulb heated up?
3. What is done to make the filament in an incandescent bulb hot?
Q4:
1. How is the filament in an incandescent bulb secured?
2. What is done to protect the filament in an incandescent bulb?
3. What mechanism is employed to protect the filament in an incandescent bulb?
Q5:
1. How is the filament protected in a halogen bulb?
2. How is the filament secured in a halogen bulb?
3. In a halogen bulb, how is the filament protected?
Q6:
1. How is energy supplied to an incandescent bulb?
2. How is an electric current supplied to an incandescent bulb?
3. Energy is supplied to an incandescent bulb in what manner?
Q7:
1. Are incandescent lights considered efficient?
2. Amongst other kinds of electric lighting, are incandescent lights efficient?
3. Are bulbs that are incandescent economical and efficient?
Q8:
1. How much of the energy provided to an incandescent bulb gets converted to light?
2. An incandescent bulb converts how much energy it uses to light?
3. How much enegry are incandescent bulbs able to convert to light?
Q9:
1. What happens to the remaining energy in an incandescent bulb?
2. What is done to the rest of the energy in an incandescent bulb?
3. What happens to the leftover energy from the incandescent bulb?
Q10:
1. An incandescent bulb creates how many lumens per watt?
2. How many lumens per watt gets created by an incandescent bulb?
3. What is the luminous efficacy of an incandescent bulb?
Q11:
1. A fluorescent bulb creates how many lumens per watt?
2. How many lumens per watt gets created by an fluorescent bulb?
3. What is the luminous efficacy of a fluorescent bulb?
Q12:
1. An LED bulb creates how many lumens per watt?
2. How many lumens per watt gets created by an LED bulb?
3. What is the luminous efficacy for an LED bulb?
Q13:
1. What are some applications for an incandescent bulb?
2. What other ways are incandescent bulbs used in?
3. What are some uses of incandescent bulbs?
Q14:
1. What is the average lifetime of an incandescent bulb?
2. How long does an incandescent bulb usually last?
3. For how long does an incandescent bulb work?
Q15:
1. What is the average lifetime of a fluorescent bulb?
2. How long does an fluorescent bulb usually last?
3. For how long does an fluorescent bulb work?
Q16:
1. What is the average lifetime of a LED bulb?
2. How long does a LED bulb usually last?
3. For how long does a LED bulb work?
