While working at the General Electric Research Laboratories,

While working at the General Electric Research Laboratories, Dr. Irving Langmuir discovered that tungsten, which has an efficiency of more than 12 lumens per watt, can be used in incandescent lamps to replace carbon filaments, which have an efficiency of only 3 lumens per watt.


A.Dr. Irving Langmuir discovered that tungsten, which has an efficiency of more than 12 lumens per watt, can be used in incandescent lamps to replace carbon filaments, which have an efficiency of only 3 lumens per watt

B. Dr. Irving Langmuir discovered that tungsten filaments have an efficiency of more than 12 lumens per watt and can be used in incandescent lamps to replace carbon filaments, which have an efficiency of only 3 lumens per watt

C. Dr. Irving Langmuir's discovery was that tungsten filaments can be used in incandescent lamps to replace carbon filaments because it has an efficiency of more than 12 lumens per watt instead of only 3 lumens per watt

D. the discovery was made by Dr. Irving Langmuir that incandescent lamps can replace carbon filaments, which have an efficiency of 3 lumens per watt, with tungsten filaments, which have an efficiency of more than 12 lumens per watt

E. the ability in incandescent lamps to replace carbon filaments, which have an efficiency of 3 lumens per watt, with tungsten filaments, which have an efficiency of more than 12 lumens per watt, was discovered by Dr. Irving Langmui

this one got me!