Q. The fluorescent dyes used in the liquid penetrant testing process are most active whenenergised with black light of what wavelengths? (Å stands for angstrom units) (Solved)
1. 2.0 × 10-7m (2000Å)
2. 2.5 × 10-7m (2500 Å)
3. 3.25 × 10-7m (3250Å)
4. 3.65 × 10-7m (3650 Å)
- d. 3.65 × 10-7m (3650 Å)