Q. What is the difference between a CFL and  an LED lamp ?1.  To produce light, a CFL uses mercury vapour and phosphor while an LED           lamp uses semiconductor material.2. The average life span of a CFL is mach longer than that of an LED lamp.3. A CFL is less energy -efficient as  compared to an LED lamp.Which of the statements given above is/are correct ? 

1. 1 only
2. 2 and 3 only
3. 1 and 3 only
4. 1,2 and 3