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A line of 11 radio transmitters is built so that each transmitter produces a signal with exactly the same amplitude and phase. What type of wave front does Huygens' principle predict in front of these transmitters if their separation is small compared to the signal's wavelength? Wave crests appear as light gray and wave troughs appear dark in the simulation. Start Build up the transmitter array from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 sources.
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| A plane wave front traveling along a line perpendicular the transmitters. |
| A plane wave front traveling along a line connecting the ends of the transmitters. |
| A circular wave front centered on the middle transmitter. |
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2.
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Two point sources act very much like a double slit as shown in the above animation. Wave crests appear as light gray and wave troughs appear darker. How will the interference pattern change if the frequency of both sources is doubled? The source separation does not change. Start Halve the frequency and observe the result.
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| The separation between wave crest and trough will be halved and the angle between the fringes will double. |
| The separation between wave crest and trough will double and the angle between the fringes will be halved. |
| The separation between wave crest and trough will be halved and the angle between the fringes will be halved. |
| The interference pattern will change very little. |
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3.
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How will the double slit interference pattern shown in the above animation change if the frequency of both sources is doubled and their separation is halved? Start Halve the separation but keep the frequency constant and observe the result.
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| The separation between wave crest and trough will be halved and the angle between the fringes will double. |
| The separation between wave crest and trough will double and the angle between the fringes will be halved. |
| The separation between wave crest and trough will be halved and the angle between the fringes will not change. |
| The interference pattern will change very little. |
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4.
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Where should the source on the right be placed in order that the first order constructive interference fringe propagates at an angle of 37 degree with respect to the x axis? The red circle can be click-dragged by pressing the edit button after you start. Distance is measured in mm. Start
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| -.25 mm |
| 0.25 mm |
| 0.50 mm |
| 0.75 mm |
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5.
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A double slit is hidden somewhere below the animation. What is the slit separation? You can measure (x,y) coordinates by click-dragging inside the animation. Assume all measurements are given nano-meters, nm. Start
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| 1 nm |
| 2 nm |
| 3 nm |
| 4 nm |
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6.
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A single slit is shown in the animation. Wave crests appear as light gray and wave troughs appear darker. How will the interference pattern change if the size of the slit is doubled? The frequency does not change. Start
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| The separation between wave crests and troughs will be halved and the angle between the fringes will double. |
| The separation between wave crest and trough will double and the angle between the fringes will be halved. |
| The separation between wave crest and trough will be halved and the angle between the fringes will be halved. |
| The interference pattern will change very little. |
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7.
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A single slit is hidden somewhere below the animation. What is the size of the slit? Distance is measured in mm when you click-drag inside the animation. Start
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| 0.5 mm |
| 1.0 mm |
| 1.5 mm |
| 2.0 mm |
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8.
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A simple diffraction grating is constructed from 5 slits. What will happen if the number of slits were increased to 10? Start Build up the grating from an array of 1, 2, 3, 4, or 5 slits.
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| The angle between the diffraction orders would increase. |
| The angle between the diffraction orders would decrease. |
| The angle between the diffraction orders would remain the same but the maxima would intensify. |
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9.
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A simple diffraction grating consisting of 5 slits is hidden somewhere below the animation. What is the slit separation? The wavelength is 0.5 micro-meter, um. Start Build up the grating from an array of 1, 2, 3, 4, or 5 slits.
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| 0.8 um |
| 1.2 um |
| 1.6 um |
| 2.0 um |
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10.
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The animation shows an E&M wave propagating in the z direction. The electric field is displayed in green and the magnetic field is displayed in red. What is the direction of polarization? You may click-drag in the animation to change the viewing angle. Start
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| The wave is unpolarized. |
| The wave is polarized in the x direction. |
| The wave is polarized in the y direction. |
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11.
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The animation shows an E&M wave propagating in the z direction and passing through a polarizer. The magnetic field is not shown. What fraction of the energy passes through the polarizer? You may click-drag in the animation to change the viewing angle. Start
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| 0.5 |
| 0.70 |
| 1.0 |
