“To emit a free electron from a metal surface a minimum amount of en

1.	“To emit a free electron from a metal surface a minimum amount of energy must be supplied”.1. It is called…….2. Give three method to supply energy to a free electron3. For metal A (tungsten) – work function is 4.52 eV for metal B (thoriated tungsten) it is 2.6 ev, for metallic (oxide coated tungsten) it is 1 eV. Which will you prefer as a good electron emitter and why?
Answer» 1. Threshold energy 2. Give light energy or heat energy 3. Work function for metallic oxide coated tungsten is small (1 ev.) Hence this material is good electron emitter.

“To emit a free electron from a metal surface a minimum amount of energy must be supplied”.1. It is called…….2. Give three method to supply energy to a free electron3. For metal A (tungsten) – work function is 4.52 eV for metal B (thoriated tungsten) it is 2.6 ev, for metallic (oxide coated tungsten) it is 1 eV. Which will you prefer as a good electron emitter and why?

Answer»

1. Threshold energy

2. Give light energy or heat energy

3. Work function for metallic oxide coated tungsten is small (1 ev.) Hence this material is good electron emitter.