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  9. Q4

PPSC PCS 2018 · Question 4 of 97

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 much 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?

Science & Tech

  1. A1 only
  2. B2 and 3 only
  3. C1 and 3 onlyCorrect
  4. D1,2 and 3

Answer: C. 1 and 3 only

Explanation

Statements 1 and 3 are correct: CFLs use mercury vapour and phosphor while LEDs use semiconductors, and CFLs are less energy-efficient; LED lamps actually last much longer than CFLs.

Source: https://cdn.mindspritesolutions.com/examrace/SPSC/Punjab-PSC/Punjab-PSC-Past-Papers/Punjab-Civil-Service-2018-Official-Paper-1-Part-1.pdf

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