When does diffraction ) ns(tq1xz5kxy yn .ps0k 5a:xoccur?

  Diamonds are highly valued because of their sparkle. This is caused by total i0*wa5l4lfgp t)llq/x nternal reflection, which reflects most of the light that falls onto a cut diamond out of the face we see. Fake gems, called 'paste', lq)l0laf*4 gwpl5x t/ are often used in jewellery because they are cheaper. However, paste gems sparkle much less than real diamonds.

The diagrams show a possible path of light through a real diamond, and another through a fake.



If:

- $n=$ refractive index;

- $n_{d}$ is the refractive index of the diamond

- $n_{f}$ is the refractive index of the fake

- $v=$ speed of light

- $v_{d}$ is the speed of light in the diamond

- $v_{f}$ is the speed of light in the fake

Which row in the table contains only statements which must be true?

  $\mathrm{K}$ is the source of a wave of frequency $25 \mathrm{~Hz}$.



The wave travels to point $M$ by two routes, $K \rightarrow L \rightarrow M$ and $K \rightarrow M$. The speed of the wave is $15 \mathrm{~m} \mathrm{~s}^{-1}$.

What is the path difference between the two waves at M in terms of the wavelength $\lambda$ of the waves?

  Ray diagrams can be used to show the reflection, refraction ap/3no9uh,r: zryz76(uf jqv;lls/ bnnd transmission of light at the boundary nryvu ; n(pb7sz:,9lhq/ rfzo3u /l6jbetween media.


In the diagram, what feature does $X$ represent?

  Which image shows the correct ray diagram for light passiprfgc782 co:p ng from air into water? ccrg87 of2:pp

  A sound source $X_{1}$ is positioned $w \; cm$ to the left of sound source $X_{2}$. Both sound sources are $y \; m$ below the detection line $A B$. $A B$ runs parallel to $X_{1} X_{2}$. When a sound detector is slowly moved along the line $A B$, a maxima is first detected at $P$, followed by a minima at $Q$, with another maxima at $R$ and a minima at $S$. $P Q R S$ are all equidistant apart with $X_{1} S=X_{2} S$.

Which one of the following is a correct expression for the wavelength of the sound?

  The diagram shows a waz 5li.)jy6q hcve approaching an aperture.


Which diagram correctly shows the resulting diffraction pattern for the wave?

  The diagram shows two waves. One wave is emitted from sourc3ak a ui +zg+3d uy2zjp*ondde; )2rb3e $s_{1}$ and travels to point $P$. The other wave is emitted from source $s_{2}$ and travels to point $P$.



What is the path difference between the waves?

  A monochromatic laser beam is shone into the surf6 5dy3nq1n ye q(zpv9qf2xgc 7ace of a tank filled with water. The effects on th1y pf cy q59(q6zeqngv7 xnd23e laser beam due to the water are observed.

How will the properties of the light be affected by the water?

  A student is investigating the interference of waves. They set up cohe 4.gdluk- 7xlprent waves produced at poildgu k.xlp47- nts $\mathrm{S}$ and $\mathrm{T}$ and travel outwards in all directions.

The line $X Y$ is halfway between $S$ and $T$ and perpendicular to the joining line $S$ and $T$. The distance $X Y$ is much greater than the distanceST.



Which line or lines would an interference pattern be seen along?

  Two waves from individual point so2fs i9zg6ya; 0zzjp s)urces meet at a point $X$. Which of the following conditions is necessary for stable interference pattern to be observed at point $X$ ?

  Which of the following options will alter the frequency of aw*yz-f sp iw om).cs., wave?

  Identical waves that begin propagation at the same time leave from two di9 ktjw7rm3f(whu,9 u.v pat1x t*(yy8 9eboisfferent sources and arrive at the same o(y 8 r7msj.ba evu91 p9tw(t ,fxt9y*hi k3wupoint point $X$. The first source is $18 \mathrm{~m}$ from point $X$. The second source is $10.5 \mathrm{~m}$ from point $X$. The waves of both sources have a wavelength of $3 \mathrm{~m}$. What is observed at $X$ ?

  When moving from matey,zj.c6(.k gwsmg kk- rial $A$ to material $B$, the direction of a ray of light moves away from the normal. If $n_{A}$ and $n_{B}$ are the refractive indices of materials $A$ and $B$ respectively, then which of the following statements is true in this situation?

  Young's double-slit experiment is setup as shown, inclut:+k(k,vb i3+ko ee/jm nm2bwding a monochromatic source, a single slit, a double slit and a screen. What is the purpose of tm,mbk2kbo3eenwi+(/ kv+jt : he single slit in this experiment?

  Which phrase correctly completes the following senjzi l ,ggosz.png*c96iy.k, e .ot..y tence?

In a ray diagram showing reflection, the angle of incidence is the angle between

  Which property of a g ncdfh .q.5 t;6so:nrwave does not change as a result of refraction?

  A ray of light is incident on a material made from three laz6/vqk:,c v1b r vtoo.yers, each having a different optical density, so that in each layer the lightb. t zqcko,1o6vrvv /: travels at a different speed.

- For layer 1: refractive index $=n_{1}$ and the speed of light $=c_{1}$

- For layer 2: refractive index $=n_{2}$ and the speed of light $=c_{2}$

- For layer 3: refractive index $=n_{3}$ and the speed of light $=c_{3}$

- Angle of incidence $=i$

- Angle of refraction $=r$

This is illustrated in the diagram below:




Which is the correct expression for $c_{3}$, the speed of light in the thirdlayer?

  The diagram below shows an arrangement usedmzd3u n /fpj,le 4n/z/ to investigate double slit interferenc,jnz 4pem//f/zn u3lde using microwaves.



The diagram below shows the view from above:



The microwaves from the transmitter are polarised. These waves are detected by the aerial in the microwave detector (probe). The aerial is a vertical metal rod.

The detector is moved along the dotted line UY. As it is moved, maximum and minimum signals are detected. Maximum signals are first detected at points $\mathrm{V}$ and $W$. The next maximum signal is detected at the position $X$.

The distances between each of the two slits, $S_{1}$ and $S_{2}$ and the microwave receiver when the aerial is in position $\mathrm{X}$ are $\mathrm{S}_{1} \mathrm{X}=$ $0.3335 \mathrm{~m}$ and $\mathrm{S}_{2} \mathrm{X}=0.3615 \mathrm{~m}$

Find the wavelength of the microwave and select the two correct reasons that explain why the signal strength falls to a minimum between $U$ and $V$, and between $V$ and W.

  Our fingerprints are made up of a series of ridges on the end of 17-drgbkvc2r the finger. These ridges can be dv2g c- 7rrbk1'read' by electronic devices.

The diagram below shows a certain type of fingerprint detector below, which works by scattering light when pressure is applied to a plastic screen. The ridges of the fingerprint press the plastic film against the glass when the finger is pressed to the screen.




When not in use, the plastic screen and the glass have a small air space between them. The diagram below shows the two possible paths for the light when the finger is pressed down.




Which row in the table correctly describes the properties of the fingerprint detector that cause the bright and dark patches on the image produced by the camera?

  Which row correctly dkd1* ca8er 5(n l5m vqy7)pxrbescribes the conditions for constructive and destructive interferen8drb*e7 1 5(qcnrmk yxl )pav5ce in a double-slit diffraction pattern?

  The double-slit equation describesp2n 6(al mosv. gl:75b m:leeo the relationship between the separation distance of the fringes oeolsm 6: lbl 7m 5oag(:2pvne.n the screen, s, the distance between the screen and the slits, $D$, the separation of the slits, $d$, and the wavelength, $\lambda$, of the light.

$$
s=\frac{\lambda D}{d}
$$

Which line gives the correct units for the quantities?

  In a Young's double-slit experiment, the spacing of the 16 kh/p2qvap1t(ejix double slits is $d$ and the distance between the slits and the screen on which fringes are formed is $D$. When monochromatic light of wavelength $\lambda$ is incident on the slits the distance between adjacent fringes on the screen is $s$.

Which row shows another arrangement that produces a fringe spacing of $s$ ?

  A double slit interference experiment is conducted us vlf2gl6 (fy :w/ +nwbb9s-mdiing monochromatic light of wavele s9ly /w: (-vg+ lwbfnm2fdb6ingth $\lambda$. The centre of the observed pattern is a bright fringe.



What is the path difference between two waves which interfere to give the second dark fringe from the centre?

  The effect of a double slit on yw3rd0s0b 6i;3 yka bkmonochromatic light is observed by the set up in k33r0akb6yw y;b ds i0the diagram below.



Interference fringes are seen on the screen.

Which of the following changes would increase the distance between the adjacent fringes?

  This diagram below shows two apertures through which planar waves are passed as- e*h.a25eiqtg,sr8ptsf o c: k0d(wb they are moving to the left. The wavefronts show crests moving in phase. Given this information, at which point will the amplitude of the waves be a minimum? 25b8.qafg t sp*h0ke(od r w-s :,etci



A flat plate made of glass has a refractive index of $n=1.52$. What is the speed of light within this material?

  When a light ray enters a denser medium mull )ksidw qyua; 2of58 9x,3and refracts, some of the characteristics of the wave will change. Whicai;2usw3q m9 xfol,k5 dy8l )uh of the following options is correct about this change?

  Which of the following images shown below best represent:s7ipt 9.ct0zgf f-twsd)vm4s the path of visible light traveli-ztt c 0 7:is 4w9gtmf)fsdv.png through a glass prism?