The diffraction grating

Monochromatic light with wavelength $5.30 \times 10^{-7}\,\text{m}$ falls normally on a diffraction grating. The first-order maximum is seen at an angle of $15.4^{\circ}$ to the direction of the incident light. What is the angle between the first-order and second-order diffraction maxima?

Feb/March 2016

A diffraction grating experiment is arranged with orange light of wavelength $600\ \text{nm}$. The grating has a slit separation of $2.00\ \mu\text{m}$. What is the angular separation $(\theta_2 - \theta_1)$ between the first-order and second-order maxima for the orange light?

Feb/March 2019

Light with wavelength $\lambda$ strikes a diffraction grating at normal incidence, as illustrated. The angle between the two second-order maxima is $\varphi$. Which expression determines the spacing between the lines on the diffraction grating?

Feb/March 2020

For a progressive wave, state what the term wavelength means.

Feb/March 2020

A beam of red laser light with wavelength $633\,\text{nm}$ is incident normally on a diffraction grating having $600$ lines per mm. The red beam is then swapped for blue laser light of wavelength $445\,\text{nm}$. A new diffraction grating is selected so that the first-order maximum of the blue light is formed at the same point on the screen as the first-order maximum of the red light from the original laser. What is the number of lines per mm in the replacement diffraction grating?

Feb/March 2021

Light with one wavelength is directed normally onto a diffraction grating. The diffraction pattern produced is shown on a screen. Which alteration would make the first-order intensity maxima lie farther apart on the screen?

Feb/March 2022

A beam of light with wavelength $567\,\text{nm}$ falls perpendicularly on a diffraction grating. The grating contains $400$ lines per $\text{mm}$. Several diffraction maxima are seen on the far side of the grating. What is the angle between the second-order maximum and the third-order maximum?

Feb/March 2025

State what the diffraction of a wave means.

May/June 2010

Which electromagnetic wave phenomenon is required to account for the spectrum formed when white light is incident on a diffraction grating?

May/June 2011

A diffraction grating containing $500$ lines per $\text{mm}$ is used to study diffraction of monochromatic light of wavelength $600\,\text{nm}$. The light is made to pass through a narrow slit, and the grating is positioned so that its lines are parallel to the slit. Light then travels through the slit and on through the grating. An observer looks at the slit through the grating at different angles, moving his head from X, parallel to the grating, through Y, opposite the slit, to Z, parallel to the grating on the other side. How many images of the slit are visible to him?

May/June 2011

Which electromagnetic wave phenomenon is required to account for the spectrum formed when white light is incident on a diffraction grating?

May/June 2011

A diffraction grating that has 500 lines per mm is employed to study the diffraction of monochromatic light with wavelength $600\,\text{nm}$. The light is first sent through a narrow slit, and the grating is positioned so that its lines run parallel to the slit. The light then travels through the slit and afterwards through the grating. An observer looks at the slit through the grating at a range of angles, shifting his head from X parallel to the grating, via Y, opposite the slit, to Z parallel to the grating on the far side. How many images of the slit does he see?

May/June 2011

The wavelength of monochromatic light is determined using a diffraction grating, as the diagram illustrates. The slit separation in the grating is $1.00 \times 10^{-6}\,\text{m}$. The separation between the first-order diffraction maxima is $70.0^{\circ}$. What is the wavelength of the light?

May/June 2012

A diffraction grating is being used to determine the wavelength of monochromatic light, as illustrated in the diagram. The slit separation in the grating is $1.00 \times 10^{-6}\,\text{m}$. The angle between the first order diffraction maxima is $70.0^\circ$. What is the wavelength of the light?

May/June 2012

A diffraction grating diffracts monochromatic light. Using this as a guide, explain what is meant by

May/June 2012

A diffraction grating is illuminated at normal incidence by monochromatic light with wavelength $5.30 \times 10^{-7}\,\text{m}$. The first order maximum appears at an angle of $15.4^{\circ}$ from the direction of the incident light. What is the angle between the first and second order diffraction maxima?

May/June 2013

Red light in a parallel beam with wavelength $700\,\text{nm}$ falls normally on a diffraction grating with $400$ lines per millimetre. How many transmitted maxima are there in total?

May/June 2013

A parallel beam of white light is directed through a diffraction grating. Orange light with wavelength $600\,\text{nm}$ in the fourth-order diffraction maximum overlaps with blue light in the fifth-order diffraction maximum. What is the wavelength of the blue light?

May/June 2014

Light is sent through a diffraction grating with $1000$ lines per cm, and the same wavelength of light is also sent through two narrow slits separated by $0.5\ \text{mm}$. In each case, the screen shows intensity maxima and minima. Which statement about how far apart the maxima are on the screen and how sharp the maxima are is correct?

May/June 2014

Monochromatic light falls on a diffraction grating, and a diffraction pattern is seen. Which row in the table shows the effect of changing the grating to one with a greater number of lines per metre?

May/June 2014

State the meaning of diffraction and the meaning of interference.

May/June 2015

A parallel beam of light with wavelength $450\,\text{nm}$ falls normally on a diffraction grating that has $300$ lines $\text{mm}^{-1}$. What is the total number of intensity maxima that are observed?

May/June 2016

A diffraction grating with $N$ lines per metre is used to deflect light of different wavelengths $\lambda$. The graph plots the relationship between the deflection angle $\theta$ and $\lambda$ for a range of wavelengths in the $n^{\text{th}}$ order interference pattern. What is the gradient of the graph?

May/June 2016

Light of a single wavelength is incident on a diffraction grating. Explain the roles of diffraction and interference in producing the first order maximum formed by the diffraction grating.

May/June 2016

A parallel beam of light with wavelength $600\,\text{nm}$ is directed at right angles onto a diffraction grating. The grating contains $300$ lines per millimetre. What is the total number of intensity maxima produced by the grating?

May/June 2017

A parallel beam of red light with wavelength $700\,\text{nm}$ falls perpendicularly on a diffraction grating with 400 lines per millimetre. What is the total number of intensity maxima produced by the grating?

May/June 2017

Monochromatic light falls on a diffraction grating, producing a diffraction pattern. Which row gives the possible effects of changing to a grating with twice as many lines per millimetre?

May/June 2017

A diffraction grating is employed to find the wavelength of light.

May/June 2017

When monochromatic light falls normally on a diffraction grating, the emerging waves have been diffracted and are coherent.

May/June 2018

The interference patterns produced by a diffraction grating and by a double slit are compared. With the diffraction grating, yellow light in the first order is observed at $30^{\circ}$ to the normal of the grating. The same light forms interference fringes on a screen $1.0\,\text{m}$ away from the double slit. The slit separation is $500$ times larger than the line spacing of the grating. What is the fringe separation on the screen?

May/June 2019

Monochromatic light is aimed at a diffraction grating, as illustrated. Which diagram could represent every possible direction of the light after it has passed through the grating that produces maximum intensity?

May/June 2019

A diffraction grating containing $300$ lines per $\text{mm}$ is illuminated by monochromatic light with wavelength $690\,\text{nm}$, creating a set of maxima (bright spots) on a screen. What is the largest number of maxima that can be seen?

May/June 2019

For a progressive water wave, state the meaning of displacement.

May/June 2019

A diffraction grating and a screen are used to find the single wavelength $\lambda$ of the light emitted by a source. Which feature is essential in this experiment?

May/June 2020

Light of wavelength $\lambda$ is incident at normal incidence on a diffraction grating. The angle between the second-order maximum and the normal to the grating is $\theta$. The graph shows how $\lambda$ varies with $\sin\theta$. How many lines per millimetre are there on the diffraction grating?

May/June 2020

Monochromatic light from a distant point source is incident normally on a diffraction grating whose lines are arranged vertically. The plane of the diffraction grating is perpendicular to the incident light. A student observes the grating from a position close to it. What could the student see?

May/June 2020

A single wavelength of light that is unknown, together with blue light of one wavelength, is each directed normally at a diffraction grating. This gives two separate diffraction patterns, one corresponding to each wavelength. For the blue light, the third-order maximum is observed at the same angle as the second-order maximum for the unknown light. The wavelength of the blue light is $480\,\text{nm}$. What is the wavelength of the unknown light?

May/June 2021

A collimated beam of light contains radiation with wavelength $420\,\text{nm}$ and radiation with wavelength $630\,\text{nm}$. It is incident normally on a diffraction grating. The diffraction maxima from the two wavelengths coincide only at an angle of $31^{\circ}$ to the direction of the incident light beam. What could the line spacing of the diffraction grating be?

May/June 2021

Light from a single wavelength source is incident normally on a diffraction grating. For each order of diffraction $n$, the diffraction angle $\theta$ is measured. The separation between neighbouring slits in the diffraction grating is $d$. A graph is drawn in order to find the wavelength of the light. Which graph should be drawn, and how is the wavelength obtained from the graph?

May/June 2021

For a progressive wave, State what wavelength means.

May/June 2021

Light with wavelength $5.4 \times 10^{-7}\,\text{m}$ is directed normally onto a diffraction grating. The spacing between neighbouring lines in the grating is $2.0 \times 10^{-6}\,\text{m}$. The light leaving the grating is received by a semicircular screen, as shown in the view from above. The grating is positioned at the centre of the semicircle, and the grating lines are vertical. How many bright spots are produced on the screen?

May/June 2022

The equation $\lambda = \dfrac{d \sin \theta}{n}$ is applied to determine the wavelength $\lambda$ of light in an experiment using a diffraction grating. The pattern produced by the diffraction grating is shown on a screen. What quantities do $n$ and $d$ stand for?

May/June 2022

A beam of light with wavelength $400\ \text{nm}$ strikes a diffraction grating normally, and the grating has $300$ lines per millimetre. After passing through the grating, the light forms a set of maxima seen on a semicircular screen, as shown. What is the total number of maxima visible on the screen?

May/June 2022

(a) Sunlight arrives as parallel rays, striking a magnifying glass at normal incidence. The magnifying glass focuses the light onto region $A$ of radius $r$, as illustrated in Fig. 5.1. In cross-section, the magnifying glass is circular with radius $5.5\,\text{cm}$. The sunlight intensity incident on the magnifying glass is $1.3\,\text{kW m}^{-2}$. Assume that every ray incident on the magnifying glass passes through it.

May/June 2022

A beam of laser light is incident normally on a diffraction grating. The diagram shows only the second-order maxima that are formed. The grating has a line spacing of $1.0 \times 10^{-6}\,\text{m}$. The angle between the two second-order maxima is $110^{\circ}$. Determine the wavelength of the light.

May/June 2023

A green light beam with wavelength $550\ \text{nm}$ falls normally on a diffraction grating and forms a diffraction pattern on a screen that is $3.5\ \text{m}$ away from the diffraction grating. The third-order maximum on the screen is $0.75\ \text{m}$ from the zeroth-order (central) maximum. Calculate the spacing between two neighbouring slits in the diffraction grating.

May/June 2023

A parallel beam of light with wavelength $600\,\text{nm}$ is incident at right angles onto a diffraction grating. The separation between neighbouring slits in the grating is $2.0 \times 10^{-6}\,\text{m}$. A screen is set up parallel to the grating, $1.50\,\text{m}$ away from it. Third-order diffraction maxima appear at the two edges of the screen, as shown. What is the separation between the two ends of the screen?

May/June 2023

Light with frequency $6.7 \\times 10^{14}\\,\\text{Hz}$ travelling through vacuum is incident perpendicularly on a diffraction grating containing $4.0 \\times 10^5$ lines $\\text{m}^{-1}$. What is the angle between the neighbouring second-order and third-order intensity maxima?

May/June 2024

A diffraction grating with $N$ lines per metre is used to diffract light of a range of wavelengths $\lambda$. The graph illustrates how the diffraction angle $\theta$ varies with $\lambda$ for several wavelengths in the $n$th order interference pattern. What is the gradient of the graph?

May/June 2024

Light of wavelength $5.50 \times 10^{-7}\,\text{m}$ from a laser falls normally on a diffraction grating. The diffracted light then falls on a semicircular screen, as seen from above. In total, 9 bright dots appear on the screen. The grating is placed at the centre of the semicircle. The lines in the grating are vertical. The spacing between neighbouring lines in the grating is $d$. What could be a possible value of $d$?

May/June 2024

Monochromatic light of a single frequency is incident normally on a diffraction grating. The resulting interference pattern of bright and dark fringes is produced on the semicircular screen shown in Fig. 6.1. The wavelength of the light is $520\,\text{nm}$. The spacing between adjacent lines in the grating is $3.8 \times 10^{-6}\,\text{m}$.

May/June 2024

Light of wavelength $680\,\text{nm}$ falls normally on a diffraction grating with $450$ lines $\text{mm}^{-1}$. What angle of diffraction corresponds to the second-order maximum in the diffraction pattern produced?

May/June 2025

A student uses a diffraction grating to find the wavelength of visible light from a source. The diffraction grating has 300 lines per mm. For each order $n$ of the intensity maxima, the student measures the angle $\theta$. A graph of $n$ against $\sin \theta$ is drawn. The plotted points are fitted with a line of best fit, and this line has gradient $G$. Which expression gives the wavelength, in m, of the visible light in terms of $G$?

May/June 2025

An electromagnetic wave falls normally on a diffraction grating. A second-order maximum appears at an angle of $30^\circ$ to the direction of the incident light. The diffraction grating contains 5000 lines per cm. Determine the wavelength of the wave.

May/June 2025

State what the meaning of diffraction is.

May/June 2025

Which electromagnetic wave would produce the greatest diffraction effect for an atomic lattice with spacing of about $10^{-10}\,\text{m}$?

Oct/Nov 2010

State the meaning of diffraction of a wave.

Oct/Nov 2010

A beam of monochromatic light is incident on a diffraction grating, as illustrated. Which diagram shows every possible direction of the light after it has passed through the grating that produces maximum intensity?

Oct/Nov 2012

Monochromatic light with wavelength $690\ \text{nm}$ is incident on a diffraction grating having $300\ \text{lines mm}^{-1}$, creating a sequence of maxima on a screen. What is the maximum number of maxima that may be seen?

Oct/Nov 2012

Describe how monochromatic light diffracts as it goes through a diffraction grating.

Oct/Nov 2012

A beam of light with wavelength $\lambda$ is incident on a diffraction grating whose slit spacing is $d$. A sequence of lines appears on a screen. What is the angle $\alpha$ between the two first order lines?

Oct/Nov 2013

Light of wavelength $\lambda$ is incident on a diffraction grating with slit spacing $d$. A set of lines is seen on a screen. What angle $\alpha$ is formed between the two first order lines?

Oct/Nov 2013

An experiment using a diffraction grating is arranged with yellow light of wavelength $600\,\text{nm}$. The grating has a slit separation of $2.00\,\mu\text{m}$. What is the angular separation $(\theta_2-\theta_1)$ between the first-order and second-order maxima for the yellow light?

Oct/Nov 2014

A diffraction grating experiment is arranged with yellow light of wavelength $600\,\text{nm}$. The grating has a slit separation of $2.00\,\mu\text{m}$. Determine the angular separation $(\theta_2 - \theta_1)$ between the first-order and second-order maxima for the yellow light.

Oct/Nov 2014

White light is made up of many wavelengths. The wavelength of red light R is about twice that of violet light V. If white light is directed normally onto a diffraction grating, a number of spectra may be produced. Which diagram shows the possible arrangement of light in the first order and the second order spectra?

Oct/Nov 2015

A diffraction grating contains $N$ lines per unit length and is set at $90^\circ$ to monochromatic light with wavelength $\lambda$. What expression gives $\theta$, the angle to the normal to the grating at which the third order diffraction peak is seen?

Oct/Nov 2015

A diffraction grating is employed to determine the wavelength of monochromatic light. The slit spacing in the grating is $1.15 \times 10^{-6}\,\text{m}$. The angle between the first order diffraction maxima is $60.0^\circ$, as illustrated in the diagram. What is the wavelength of the light?

Oct/Nov 2016

A diffraction grating is employed to determine the wavelength of monochromatic light. The separation of the slits in the grating is $1.15 \times 10^{-6}\,\text{m}$. The angle between the first order diffraction maxima is $60.0^\circ$, as illustrated in the diagram. Calculate the wavelength of the light.

Oct/Nov 2016

State what the diffraction of a wave means.

Oct/Nov 2016

State what the diffraction of a wave means.

Oct/Nov 2016

As shown in the diagram, a diffraction grating is employed to determine the wavelength of monochromatic light. The spacing of the slits in the grating is $1.00 \times 10^{-6}\,\text{m}$. The angle between the first order diffraction maxima is $70.0^\circ$. What is the wavelength of the light?

Oct/Nov 2017

A beam of light is composed of two wavelengths, $436\,\text{nm}$ and $654\,\text{nm}$. A diffraction grating with $5.00 \times 10^{5}\,\text{lines m}^{-1}$ forms a diffraction pattern in which the second order for one wavelength appears at the identical angle $\theta$ as the third order for the other wavelength. What is the angle $\theta$?

Oct/Nov 2018

A parallel beam of monochromatic light with wavelength $\lambda$ falls normally on a diffraction grating $G$. As shown, the angle between the directions of the two second-order diffracted beams at $P_1$ and $P_2$ is $\alpha$. What is the grating line spacing?

Oct/Nov 2018

A parallel beam of white light is directed normally at a diffraction grating. The second-order and third-order spectra overlap partly. Which wavelength in the third-order spectrum is seen at the same angle as the wavelength of $600\,\text{nm}$ in the second-order spectrum?

Oct/Nov 2018

A beam of red light with wavelength $640\,\text{nm}$ is directed normally onto a diffraction grating whose line spacing is $1.7 \times 10^{-6}\,\text{m}$, as illustrated in Fig. 5.1. The light’s second-order diffraction maximum is observed at an angle $\theta$ to the incident-light direction.

Oct/Nov 2018

Monochromatic light of wavelength $720\,\text{nm}$ from laser X is directed normally at a diffraction grating, and a diffraction pattern is formed. Light from laser Y is then also directed normally at the same grating. The third-order maximum produced by laser Y appears at the same position as the second-order maximum produced by laser X. What is the wavelength of the light from laser Y?

Oct/Nov 2019

A diffraction grating with line spacing $d$ is illuminated by monochromatic light of frequency $f$. The speed of light is $c$. Which expression may be used to find the greatest order of intensity maximum formed by the grating?

Oct/Nov 2019

An electromagnetic wave is directed normally onto a diffraction grating. A second-order maximum appears at an angle of $30^{\circ}$ to a normal to the grating. The grating contains $5000$ lines per $\text{cm}$. What is the wavelength of the wave?

Oct/Nov 2019

Light with wavelength $567\,\text{nm}$ falls perpendicularly on a diffraction grating. The grating contains $400$ lines per mm. Several diffraction maxima are seen on the opposite side of the grating. What is the angular separation between the second-order maximum and the third-order maximum?

Oct/Nov 2019

Waves of light leaving the slits in a diffraction grating are coherent, so they create an interference pattern.

Oct/Nov 2019

A parallel beam of white light is incident on a diffraction grating. Orange light with wavelength $600\ \text{nm}$ in the fourth-order diffraction maximum overlaps with blue light in the fifth-order diffraction maximum. Determine the wavelength of the blue light.

Oct/Nov 2020

Monochromatic light is directed onto a diffraction grating. Seven bright spots are seen on a screen. Which change would increase the number of bright spots observed?

Oct/Nov 2020

A diffraction grating is illuminated normally by light with wavelength $5.30 \times 10^{-7}\,\text{m}$. The first-order maximum is seen at an angle of $15.4^\circ$ to the direction of the incident light. What is the angle between the first-order and second-order diffraction maxima?

Oct/Nov 2020

A microphone, linked to a cathode-ray oscilloscope (CRO), picks up a sound wave. The trace shown on the CRO screen is given in Fig. 5.1. The CRO time-base setting is $2.0 \times 10^{-5}\,\text{s cm}^{-1}$.

Oct/Nov 2020

Green light falls normally on a diffraction grating and produces a diffraction pattern on a screen far away. Which change, on its own, would reduce the spacing between the diffraction maxima on the screen?

Oct/Nov 2021

A beam of light with wavelength $5.5 \times 10^{-7}\,\text{m}$ falls normally on a diffraction grating. The separation between the second-order diffraction maxima is $80^\circ$, as illustrated. Determine the number of lines per metre of the diffraction grating.

Oct/Nov 2021

A beam of green light falls normally on a diffraction grating. A number of bright spots appear on a screen on the far side of the grating, as shown. Which pair of changes could produce bright spots at exactly the same angles as before?

Oct/Nov 2021

A diffraction grating contains $4.00 \times 10^5$ lines per metre. Light with wavelength $589 \times 10^{-9}\,\text{m}$ falls normally on the diffraction grating. What is the angle between the second-order maximum and the line of travel of the incident beam of light?

Oct/Nov 2022

Red light with one wavelength is sent through a diffraction grating. Bright spots appear on a screen, as shown. The red light is then changed to white light. Which diagram, drawn to the same scale, could show a possible pattern of bright light on the screen?

Oct/Nov 2022

Which characteristic of a light wave can be found using a diffraction grating?

Oct/Nov 2022

A beam of red light with wavelength $720\,\text{nm}$ is directed normally onto a diffraction grating, creating a diffraction pattern on a screen that lies parallel to the grating. This red-light beam is then substituted by a beam of electromagnetic radiation with wavelength $X$, which also strikes the same diffraction grating at normal incidence. The third-order maximum for the radiation of wavelength $X$ appears at the same point on the screen as the second-order maximum for the red light. Determine wavelength $X$.

Oct/Nov 2023

Light of wavelength $690\,\text{nm}$ falls on a diffraction grating with 300 lines per mm, so a sequence of bright maxima is formed on a screen. How many bright spots are formed altogether?

Oct/Nov 2023

A diffraction grating is being used to determine the wavelength of light. The slit separation in the grating is $1.15 \times 10^{-6}\,\text{m}$. The angle between the first-order diffraction maxima is $60.0^{\circ}$, as shown. What is the wavelength of the light?

Oct/Nov 2023

As illustrated in Fig. 5.1, a beam of vertically polarised light is incident normally on a polarising filter.

Oct/Nov 2023

Light of wavelength $\lambda$ is directed normally onto a diffraction grating that has a total of $N$ lines across width $w$. A second order maximum is seen at a diffraction angle of $\theta$. What is the value of $N$?

Oct/Nov 2024

The diagram illustrates visible light falling normally on a diffraction grating. An intensity pattern with maxima is formed on the screen. A line joining the centre of the fourth order intensity maximum to the centre of the diffraction grating makes an angle of $53^\circ$ with the centre line. The grating has a line spacing of $2.7 \times 10^{-6}\,\text{m}$. What is the wavelength of the incident light?

Oct/Nov 2024

A beam of vertically polarised light with wavelength $540\,\text{nm}$ falls normally on a diffraction grating, as illustrated in Fig. 4.1. The grating has a line spacing of $5.0 \times 10^{-6}\,\text{m}$. The transmitted light falls on a circular screen, with the diffraction grating at the circle centre $X$. The central bright fringe appears at point $O$ on the screen and has intensity $I_0$. $P$ is a point on the screen where line $XP$ makes a variable angle $\theta$ with line $XO$. The light intensity $I$ at $P$ changes with $\theta$.

Oct/Nov 2025

State what diffraction of a wave means.

Oct/Nov 2025