At a Certain Point and a Certain Time the Electric

question 38

Multiple Choice

At a certain point and a certain time the electric field of an electromagnetic wave is in the negative z direction and the magnetic field is in the positive y direction.Which of the following statements is true?

• A)Energy is being transported in the positive x direction but half a cycle later, when the electric field is in the opposite direction, it will be transported in the negative x direction.
• B)Energy is being transported in the positive x direction and half a cycle later, when the electric field is in the opposite direction, it will still be transported in the positive x direction.
• C)Energy is being transported in the negative x direction but half a cycle later, when the electric field is in the opposite direction, it will be transported in the positive x direction.
• D)Energy is being transported in the negative x direction and half a cycle later, when the electric field is in the opposite direction, it will still be transported in the negative x direction.
• E)None of the above is true.

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Definitions:

Medulla

An essential part of the brainstem involved in regulating breathing, heart rate, and other autonomic functions.

Cerebral Cortex

The outer layer of neural tissue of the cerebrum of the brain, playing a key role in memory, attention, perception, awareness, thought, language, and consciousness.

Hypothalamus

A region of the brain below the thalamus that coordinates both the autonomic nervous system and the activity of the pituitary, controlling body temperature, hunger, thirst, fatigue, sleep, and circadian cycles.

Limbic System

A complex system of nerves and networks in the brain, involving several areas near the edge of the cortex concerned with instinct and mood. It controls the basic emotions (fear, pleasure, anger) and drives (hunger, sex, dominance, care of offspring).