Question

Gurmit wanted to perform activity 16.8 using a laser torch. Her teacher advised her not to do so. Can you explain the basis of teachers advice?

Answer 1

We know the properties of laser light that they are sharply focused, spread little, are coherent and monochromatic in nature. These can be discussed here.

Complete step by step answer
We know by various laser light properties that the light is of high coherence and intensity since light is focused. If we compare it to a normal torch, the difference in intensity is large. It means that power per unit area is also large. The coherent property makes it to be focused to a spot. These all factors can make a laser torch dangerous. The teacher advised it to avoid any accidents to happen as when directly projected in a person's eye it can cause serious damage to the eye.

Additional information
Laser operations are possible due to stimulated emission. Stimulated emission is the principle of lasers. We know that an electron in an atom can absorb energy from a photon if this energy corresponds to energy level difference for transition. So, a photon can make an atom return to ground state on emission of another photon of the same energy. This process is called stimulated as it requires external photons. There are many types of Laser such as gas lasers, liquid dye lasers, solid state lasers and semiconductor lasers. Lasers have many applications nowadays like for communication, cutting, welding and many more.

Note: Laser is not a word, it's actually an acronym, which stands for '' Light Amplification by the Stimulated Emission of Radiation. It must be kept in mind that for stimulated emission to be prominent, the number of photons emitted must be more than the number of photons absorbed.