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What are the charge carriers when an electric current (i) passes through a semiconductor; (ii) passes through an electrolyte? - Leaving Cert Physics - Question g - 2008
Question g
What are the charge carriers when an electric current (i) passes through a semiconductor; (ii) passes through an electrolyte?
Worked Solution & Example Answer:What are the charge carriers when an electric current (i) passes through a semiconductor; (ii) passes through an electrolyte? - Leaving Cert Physics - Question g - 2008
Step 1
(i) passes through a semiconductor
Answer
When an electric current passes through a semiconductor, the primary charge carriers are electrons and holes. Electrons carry a negative charge and are the result of the movement of negatively charged particles. In semiconductors, when an electron is excited from the valence band to the conduction band, it leaves behind a vacancy known as a hole. This hole can be considered a positive charge carrier because it represents the absence of an electron.
Step 2
(ii) passes through an electrolyte
Answer
In an electrolyte, the charge carriers are ions. When an electric current flows through an electrolyte solution, the ions (both positive and negative) move towards the respective electrodes. Cations (positively charged ions) migrate towards the cathode, while anions (negatively charged ions) move towards the anode, thus facilitating the flow of electric current.