Question 6
(a) State two dangers associated with the use of laser.
(b) A laser produces a beam of light of frequency 4.82 x 1014Hz. Calculate the energy of a photon in the laser beam. [h=6.6 x 10-34Js]
Observation
This question was not popular among candidates. In (a), some candidates responded that laser causes cancer which indicates that they had no idea what a laser is like. Candidates had no problem in (b) except those with numerical problems. Performance was fair.
The expected answer is
(a) Dangers Associated with laser
- Damage to (human) eye;
- Fire outbreak;
- Skin burn/tanning;
- Explosion.
(b)
6.6 x 10-34 x 4.82 x 1014
3.18 x 10-19 J