Transistors

The core of a transformer is laminated to minimize the energy losses from eddy currents. This reduces the interference of the primary coil with the secondary coil and thus, the energy transfer becomes efficient. When the transformer core heats up, the energy is lost due to the eddy currents. This is electrical energy given up in the form of heat. To prevent this, the transformer core is laminated.

Also Read: Power Transformers

To solve this problem, we need to understand the behavior of charge carriers in semiconductors when an external electric field is applied. Let's consider both -type and -type semiconductors:

1. Charge Carriers in Semiconductors:
   • In an -type semiconductor, the majority charge carriers are electrons.
   • In a -type semiconductor, the majority charge carriers are holes.
2. Mobility of Charge Carriers:
   • Electrons generally have higher mobility than holes due to their smaller effective mass.
   • The drift velocity, , of charge carriers under an electric field is given by , where is the mobility and is the electric field.
3. Current Due to Charge Carriers:
   • The current density, , due to drift in an electric field is given by , where is the carrier concentration, is the charge of an electron, and is the drift velocity.
   • Given that the electron concentration in the -type is equal to the hole concentration in the -type semiconductor, and knowing that electrons have higher mobility than holes ( ), we can infer that the current in the -type will be greater.
4. Conclusion: With equal carrier concentrations and a higher mobility for electrons than holes, the current in the -type semiconductor will be greater than in the -type semiconductor. Thus, the correct answer is:

current in n-type > current in p-type