1. Q32.1
The drawing shows an electromagnetic wave in a vacuum. The wave is propagating
1. in the positive x-direction
2. in the negative x-direction
3. in the positive y-direction
4. in the positive z-direction
5. none of the above

2. A32.1
The drawing shows an electromagnetic wave in a vacuum. The wave is propagating
1. in the positive x-direction
2. in the negative x-direction
3. in the positive y-direction
4. in the positive z-direction
5. none of the above

3. Q32.2
A sinusoidal electromagnetic wave in a vacuum is propagating in the positive z-direction.
At a certain point in the wave at a certain instant in time, the electric field points in the negative x-direction.
At the same point and at the same instant, the magnetic field points
1. in the positive y-direction
2. in the negative y-direction
3. in the positive z-direction
4. in the negative z-direction
5. none of the above

4. A32.2
A sinusoidal electromagnetic wave in a vacuum is propagating in the positive z-direction.
At a certain point in the wave at a certain instant in time, the electric field points in the negative x-direction.
At the same point and at the same instant, the magnetic field points
1. in the positive y-direction
2. in the negative y-direction
3. in the positive z-direction
4. in the negative z-direction
5. none of the above

5. Q32.3
In a sinusoidal electromagnetic wave in a vacuum, the electric field has only an x-component. This component is given by
Ex = Emax cos (ky + wt)
Which statement about this wave is correct?
1. the wave propagates in the +z-direction, and the magnetic field has only a y-component
2. the wave propagates in the –z-direction, and the magnetic field has only a y-component
3. the wave propagates in the +y-direction, and the magnetic field has only a z-component
4. the wave propagates in the –y-direction, and the magnetic field has only a z-component
5. none of the above

6. A32.3
In a sinusoidal electromagnetic wave in a vacuum, the electric field has only an x-component. This component is given by
Ex = Emax cos (ky + wt)
Which statement about this wave is correct?
1. the wave propagates in the +z-direction, and the magnetic field has only a y-component
2. the wave propagates in the –z-direction, and the magnetic field has only a y-component
3. the wave propagates in the +y-direction, and the magnetic field has only a z-component
4. the wave propagates in the –y-direction, and the magnetic field has only a z-component
5. none of the above

7. Q32.4
In a sinusoidal electromagnetic wave in a vacuum, the magnetic energy density
1. is the same at all points in the wave
2. is maximum where the electric field has its greatest value
3. is maximum where the electric field is zero
4. none of the above

8. A32.4
In a sinusoidal electromagnetic wave in a vacuum, the magnetic energy density
1. is the same at all points in the wave
2. is maximum where the electric field has its greatest value
3. is maximum where the electric field is zero
4. none of the above

9. Q32.5
The drawing shows a sinusoidal electromagnetic wave in a vacuum at one instant of time at points between x = 0 and x = l. At this instant, at which values of x does the instantaneous Poynting vector have its maximum magnitude?
1. x = 0 and x = l only
2. x = l/4 and x = 3l/4 only
3. x = l/2 only
4. x = 0, x = l/2, and x = l

10. A32.5
The drawing shows a sinusoidal electromagnetic wave in a vacuum at one instant of time at points between x = 0 and x = l. At this instant, at which values of x does the instantaneous Poynting vector have its maximum magnitude?
1. x = 0 and x = l only
2. x = l/4 and x = 3l/4 only
3. x = l/2 only
4. x = 0, x = l/2, and x = l

11. Q32.6
The drawing shows a sinusoidal electromagnetic standing wave. The average Poynting vector in this wave
1. points along the x-axis
2. points along the y-axis
3. points along the z-axis
4. is zero
5. none of the above

12. A32.6
The drawing shows a sinusoidal electromagnetic standing wave. The average Poynting vector in this wave
1. points along the x-axis
2. points along the y-axis
3. points along the z-axis
4. is zero
5. none of the above

13. Q32.7
The illustration shows the wavelengths of different colors of light in a vacuum. The illustration tells us that in a vacuum,
1. red light has higher frequency and moves faster than violet light
2. red light has higher frequency and moves slower than violet light
3. red light has lower frequency and moves faster than violet light
4. red light has lower frequency and moves slower than violet light
5. none of the above

14. A32.7
The illustration shows the wavelengths of different colors of light in a vacuum. The illustration tells us that in a vacuum,
1. red light has higher frequency and moves faster than violet light
2. red light has higher frequency and moves slower than violet light
3. red light has lower frequency and moves faster than violet light
4. red light has lower frequency and moves slower than violet light
5. none of the above