State PCS PYQPrelims 2021

UPPCS · Question 126

Which of the following types of glass can cut off ultraviolet rays?

  1. Soda glass
  2. Pyrex glass
  3. Jena glass
  4. Crookes glass
Show answer & explanation

Answer: (D) Crookes glass

Explanation

Crookes glass contains cerium oxide, which absorbs UV; it is used in sunglasses.