Chapter 26, Problem 5STP

To determine

To Choose: The correct option.

Answer to Problem 5STP

The correct option is (A).

Explanation of Solution

Introduction:

An electromagnetic wave is composed of the electric field ( $E$ ) and the magnetic field $\overrightarrow{B}$ which vibrate perpendicular to each other.

(A) There is piezoelectricity when an alternating voltage is applied across the crystal, and then it produces the electromagnetic waves. In the given case, on a piezoelectric quartz crystal, a direct current voltage is applied. It cannot showcase piezoelectricity property, and therefore no electromagnetic waves are produced.

(B) The current passing through a wire contained within a plastic pipe can produce the magnetic field which in turn generate the EMF back due to alternating current. The electromagnetic waves are produced by coupling the electric field and the magnetic field. Thus, the alternating current can produce electromagnetic waves when passes through a wire.

(C) The current passing through a coil and capacitor circuit with molecules size resonant cavity can produce electromagnetic waves at the resonant frequency.

(D) The high energy electrons strike the metal target and produce the X-ray, which are electromagnetic waves in nature.

Conclusion:

Hence, the statement (A) does not create an electromagnetic wave.