Flag 8 grade science> What is the basic principle of electric p...
question mark

What is the basic principle of electric pen ? Explain how it can be used for writing.

Harshit Singh , 4 Years ago
Grade 12th pass
anser 1 Answers
Pawan Prajapati

Last Activity: 4 Years ago

Electric charge on ions is used for writing with an electric pen. Method : Take a filter paper soaked in potassium iodide solution to which a pinch of starch is added. Place the filter paper on a metal sheet. Connect the negative terminal of battery to the metal sheet. Write on the paper with the end of the wire connected to the positive terminal.The writing appears on the paper. This happens because the when current is passed, the K+ ions are attracted to the metal sheet. The iodide ions (I- ) react with starch to turn blue black.

star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments