AP Physics 2 Flashcards: Diffraction

What this deck covers

This deck focuses on Diffraction, giving you a quick way to review the definitions, rules, and examples that matter most for AP Physics 2.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What does $a$ represent in the single-slit diffraction formula?

Answer: $a$ represents the width of the slit. This is the physical aperture dimension that controls diffraction spreading.

Flashcard 2: What is the primary difference between diffraction and refraction?

Answer: Diffraction is bending around obstacles; refraction is bending through different media. Diffraction involves wave spreading; refraction involves speed changes.

Flashcard 3: What is the role of the slit separation $d$ in double-slit diffraction?

Answer: $d$ is the distance between the centers of the two slits. This spacing determines the fringe separation in the pattern.

Flashcard 4: What happens to diffraction when the wavelength increases?

Answer: Diffraction increases with an increase in wavelength. Longer waves bend more around obstacles of the same size.

Flashcard 5: State the condition for the first minimum in single-slit diffraction.

Answer: $a \, \sin \theta = \lambda$. This is where $m = 1$ in the general minima formula.

Flashcard 6: What is the effect of increasing the number of slits in a diffraction grating?

Answer: Increases the sharpness and brightness of maxima. More slits create narrower, more intense diffraction peaks.

Flashcard 7: State the principle of superposition in wave interference.

Answer: The principle that the resultant displacement is the sum of individual displacements. This allows calculation of net wave amplitude at any point.

Flashcard 8: What is the significance of the zero-order maximum in diffraction?

Answer: The zero-order maximum is the brightest and occurs directly opposite the source. This is the undiffracted beam with $m = 0$ in the grating equation.

Flashcard 9: What effect does increasing the number of grooves on a grating have?

Answer: Increases the resolution of the diffraction pattern. More grooves per unit length create sharper spectral lines.

Flashcard 10: How does light wavelength affect diffraction patterns?

Answer: Longer wavelengths produce wider diffraction patterns. Greater wavelength means more bending around apertures.

Flashcard 11: How is the diffraction pattern affected by the wavelength of light?

Answer: A longer wavelength results in a wider diffraction pattern. This follows from the inverse relationship in diffraction formulas.

Flashcard 12: What is the relationship between slit separation and diffraction angle in gratings?

Answer: Larger slit separation results in smaller diffraction angles. Larger $d$ requires smaller $\sin \theta$ for the same wavelength.

Flashcard 13: Why do diffraction patterns occur?

Answer: Diffraction patterns occur due to interference of waves bending around obstacles. Wave spreading creates regions of constructive and destructive interference.

Flashcard 14: Define constructive interference.

Answer: Constructive interference occurs when waves combine to produce a larger amplitude. This happens when waves arrive in phase with each other.

Flashcard 15: What is the primary difference between diffraction and refraction?

Answer: Diffraction is bending around obstacles; refraction is bending through different media. Diffraction involves wave spreading; refraction involves speed changes.

Flashcard 16: Identify the primary factor that determines the extent of diffraction.

Answer: The wavelength of the wave relative to the size of the obstacle or opening. Comparable sizes produce the strongest diffraction effects.

Flashcard 17: Explain the term 'diffraction grating'.

Answer: A diffraction grating is an optical component with a pattern of regular lines or grooves. These create multiple coherent sources for enhanced diffraction effects.

Flashcard 18: Identify the primary variable affecting the angular position of diffraction minima.

Answer: The wavelength of the incident wave. Wavelength directly determines the angular scale of the pattern.

Flashcard 19: How is the diffraction pattern affected by the wavelength of light?

Answer: A longer wavelength results in a wider diffraction pattern. This follows from the inverse relationship in diffraction formulas.

Flashcard 20: What is diffraction?

Answer: Diffraction is the bending of waves around obstacles or through openings. This occurs when wave dimensions are comparable to obstacle/opening sizes.

Flashcard 21: State the condition for maxima in double-slit diffraction.

Answer: $d \sin \theta = m \lambda$ where $m$ is an integer. This gives bright fringe positions in the interference pattern.

Flashcard 22: State the relationship between frequency and diffraction.

Answer: Higher frequency waves diffract less than lower frequency waves. Higher frequency means shorter wavelength and less diffraction.

Flashcard 23: State the formula for path difference in double-slit diffraction.

Answer: $\Delta r = d \sin \theta$. This represents the extra distance traveled by one wave.

Flashcard 24: What effect does increasing the number of grooves on a grating have?

Answer: Increases the resolution of the diffraction pattern. More grooves per unit length create sharper spectral lines.

Flashcard 25: What is the effect of increasing the number of slits in a diffraction grating?

Answer: Increases the sharpness and brightness of maxima. More slits create narrower, more intense diffraction peaks.

Flashcard 26: What is the effect of increasing slit width on diffraction?

Answer: Increasing slit width decreases the extent of diffraction. Wider slits concentrate more energy in the forward direction.

Flashcard 27: What is the condition for the central maximum in single-slit diffraction?

Answer: The central maximum occurs at $\theta = 0$. This is the straight-through direction with maximum intensity.

Flashcard 28: What does the term 'fringe spacing' refer to?

Answer: The distance between adjacent maxima or minima in a diffraction pattern. This measures the separation between repeating pattern features.

Flashcard 29: How does wavelength affect the order of diffraction maxima?

Answer: Longer wavelengths produce lower-order maxima at larger angles. Longer wavelengths satisfy the grating equation at larger angles.

Flashcard 30: What role does coherence play in diffraction patterns?

Answer: Coherence is necessary for producing clear and stable diffraction patterns. Coherent sources maintain constant phase relationships for interference.

Flashcard 31: Identify the relationship between slit separation and fringe spacing in diffraction grating.

Answer: Fringe spacing decreases as slit separation increases. Closer slits create wider-spaced interference fringes.

Flashcard 32: How does light wavelength affect diffraction patterns?

Answer: Longer wavelengths produce wider diffraction patterns. Greater wavelength means more bending around apertures.

Flashcard 33: What is the diffraction limit?

Answer: The diffraction limit is the smallest angular separation resolved by a lens or aperture. This sets the minimum resolvable detail size in optical systems.

Flashcard 34: How is the angle $\theta$ related to diffraction?

Answer: $\theta$ is the angle at which minima or maxima occur in diffraction. This angle is measured from the normal to the slit plane.

Flashcard 35: State the condition for the first minimum in single-slit diffraction.

Answer: $a \, \sin \theta = \lambda$. This is where $m = 1$ in the general minima formula.

Flashcard 36: What does the term 'order' refer to in a diffraction pattern?

Answer: Order refers to the sequence number of maxima in a diffraction pattern. Order $m$ counts the number of wavelengths in path difference.

Flashcard 37: What is the role of the slit separation $d$ in double-slit diffraction?

Answer: $d$ is the distance between the centers of the two slits. This spacing determines the fringe separation in the pattern.

Flashcard 38: Identify the primary variable affecting the angular position of diffraction minima.

Answer: The wavelength of the incident wave. Wavelength directly determines the angular scale of the pattern.

Flashcard 39: State the formula for single-slit diffraction minima.

Answer: $a \, \sin \theta = m \lambda$ where $m$ is an integer (except 0). This gives destructive interference positions where intensity is minimum.

Flashcard 40: What effect does decreasing the slit width have on the central maximum?

Answer: Decreasing slit width increases the width of the central maximum. Smaller slits spread light over larger angular ranges.

Flashcard 41: Identify the central maximum in a diffraction pattern.

Answer: The central maximum is the brightest and widest part of the pattern. It has the highest intensity and spans from first minimum to first minimum.

Flashcard 42: What is the key difference between single and multiple slit diffraction patterns?

Answer: Multiple slits produce sharper and more numerous maxima. Multiple slits create additional interference that sharpens the pattern.

Flashcard 43: Define destructive interference.

Answer: Destructive interference occurs when waves combine to produce a smaller amplitude. This occurs when waves arrive out of phase with each other.

Flashcard 44: How is the angle $\theta$ related to diffraction?

Answer: $\theta$ is the angle at which minima or maxima occur in diffraction. This angle is measured from the normal to the slit plane.

Flashcard 45: Identify the central maximum in a diffraction pattern.

Answer: The central maximum is the brightest and widest part of the pattern. It has the highest intensity and spans from first minimum to first minimum.

Flashcard 46: State the relationship between frequency and diffraction.

Answer: Higher frequency waves diffract less than lower frequency waves. Higher frequency means shorter wavelength and less diffraction.

Flashcard 47: How does wavelength affect the order of diffraction maxima?

Answer: Longer wavelengths produce lower-order maxima at larger angles. Longer wavelengths satisfy the grating equation at larger angles.

Flashcard 48: What does $\lambda$ represent in the diffraction formula?

Answer: $\lambda$ is the wavelength of the incident wave. This determines the scale of the diffraction pattern features.

Flashcard 49: What does the term 'fringe spacing' refer to?

Answer: The distance between adjacent maxima or minima in a diffraction pattern. This measures the separation between repeating pattern features.

Flashcard 50: What is the condition for the central maximum in single-slit diffraction?

Answer: The central maximum occurs at $\theta = 0$. This is the straight-through direction with maximum intensity.

Flashcard 51: How does the slit width affect the diffraction pattern?

Answer: Narrower slits produce wider diffraction patterns. Smaller openings cause greater spreading due to wave properties.

Flashcard 52: What does the term 'order' refer to in a diffraction pattern?

Answer: Order refers to the sequence number of maxima in a diffraction pattern. Order $m$ counts the number of wavelengths in path difference.

Flashcard 53: State the formula for single-slit diffraction minima.

Answer: $a \, \sin \theta = m \lambda$ where $m$ is an integer (except 0). This gives destructive interference positions where intensity is minimum.

Flashcard 54: State the condition for maxima in double-slit diffraction.

Answer: $d \sin \theta = m \lambda$ where $m$ is an integer. This gives bright fringe positions in the interference pattern.

Flashcard 55: What is diffraction?

Answer: Diffraction is the bending of waves around obstacles or through openings. This occurs when wave dimensions are comparable to obstacle/opening sizes.

Flashcard 56: What is the diffraction limit?

Answer: The diffraction limit is the smallest angular separation resolved by a lens or aperture. This sets the minimum resolvable detail size in optical systems.

Flashcard 57: Identify the primary factor that determines the extent of diffraction.

Answer: The wavelength of the wave relative to the size of the obstacle or opening. Comparable sizes produce the strongest diffraction effects.

Flashcard 58: What is the effect of increasing slit width on diffraction?

Answer: Increasing slit width decreases the extent of diffraction. Wider slits concentrate more energy in the forward direction.

Flashcard 59: Identify the relationship between slit separation and fringe spacing in diffraction grating.

Answer: Fringe spacing decreases as slit separation increases. Closer slits create wider-spaced interference fringes.

Flashcard 60: Explain the term 'diffraction grating'.

Answer: A diffraction grating is an optical component with a pattern of regular lines or grooves. These create multiple coherent sources for enhanced diffraction effects.

Flashcard 61: What does $\lambda$ represent in the diffraction formula?

Answer: $\lambda$ is the wavelength of the incident wave. This determines the scale of the diffraction pattern features.

Flashcard 62: What is the key difference between single and multiple slit diffraction patterns?

Answer: Multiple slits produce sharper and more numerous maxima. Multiple slits create additional interference that sharpens the pattern.

Flashcard 63: Why do diffraction patterns occur?

Answer: Diffraction patterns occur due to interference of waves bending around obstacles. Wave spreading creates regions of constructive and destructive interference.

Flashcard 64: What is the significance of the zero-order maximum in diffraction?

Answer: The zero-order maximum is the brightest and occurs directly opposite the source. This is the undiffracted beam with $m = 0$ in the grating equation.

Flashcard 65: How does the slit width affect the diffraction pattern?

Answer: Narrower slits produce wider diffraction patterns. Smaller openings cause greater spreading due to wave properties.

Flashcard 66: State the formula for path difference in double-slit diffraction.

Answer: $\Delta r = d \sin \theta$. This represents the extra distance traveled by one wave.

Flashcard 67: State the principle of superposition in wave interference.

Answer: The principle that the resultant displacement is the sum of individual displacements. This allows calculation of net wave amplitude at any point.

Flashcard 68: What is the formula for the angular width of the central maximum?

Answer: $\Delta \theta = \frac{2 \lambda}{a}$. This spans from first minimum to first minimum on opposite sides.

Flashcard 69: What is the relationship between slit separation and diffraction angle in gratings?

Answer: Larger slit separation results in smaller diffraction angles. Larger $d$ requires smaller $\sin \theta$ for the same wavelength.

Flashcard 70: What role does coherence play in diffraction patterns?

Answer: Coherence is necessary for producing clear and stable diffraction patterns. Coherent sources maintain constant phase relationships for interference.

Flashcard 71: What happens to diffraction when the wavelength increases?

Answer: Diffraction increases with an increase in wavelength. Longer waves bend more around obstacles of the same size.

Flashcard 72: What effect does decreasing the slit width have on the central maximum?

Answer: Decreasing slit width increases the width of the central maximum. Smaller slits spread light over larger angular ranges.

Flashcard 73: What does $a$ represent in the single-slit diffraction formula?

Answer: $a$ represents the width of the slit. This is the physical aperture dimension that controls diffraction spreading.

Flashcard 74: What is the formula for the angular width of the central maximum?

Answer: $\Delta \theta = \frac{2 \lambda}{a}$. This spans from first minimum to first minimum on opposite sides.