Two Radio Antennas Are $120 \mathrm {~m}$ Apart on a North-South Line

question 59

Multiple Choice

Two radio antennas are $120 \mathrm {~m}$ apart on a north-south line. The two antennas radiate in phase at a frequency of $5.6 \mathrm { MHz }$ . All radio measurements are made far from the antennas. What is the smallest angle, reckoned north of east from midway between the antennas, at which destructive interference of the two radio waves occurs? $\left( c = 3.00 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } \right)$

• A) \(9.7 ^ { \circ }\)
• B) \(6.4 ^ { \circ }\)
• C) \(19 ^ { \circ }\)
• D) \(16 ^ { \circ }\)
• E) \(13 ^ { \circ }\)

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Definitions:

Linear

Describing a structure, progression, or relationship that follows a straight line or in simpler terms, one that proceeds from one stage to the next in a single series of steps.

Ammonia Molecule

A compound made of nitrogen and hydrogen with the formula NH3, characterized by a sharp smell and often used in fertilizers.

Trigonal Pyramidal

A molecule shape where a central atom is surrounded by three atoms at the corners of a pyramid, which has a triangular base.

Central Atom

The atom in a molecule or polyatomic ion that is surrounded by other atoms, forming the basis of the molecule's geometry.