Topic: Electromagnetics
Which of the following statement is correct?
- A. In semiconductors, electron and holes move in an electric field and in the same direction
- B. Electric field density is exactly equal to the sum of electric field intensity and polarization
- C. Ampere's circuital law states that the line integral of $\overline{H}$ about any closed path is exactly equal to the direct current enclosed by that path
- D. None of the above
Answer: C. Ampere's circuital law states that the line integral of $\overline{H}$ about any closed path is exactly equal to the direct current enclosed by that path
Explanation: Option (c) correctly states Ampere's Circuital Law for static magnetic fields: $\oint \overline{H} \cdot d\overline{l} = I_{enclosed}$. Option (a) is incorrect because electrons and holes move in opposite directions under an electric field. Option (b) is incorrect because Electric flux density $D = \epsilon_0 E + P$.