Diamonds are highly valued because of their sparkle. This is camhj xswbc/ylw)j h50 ya1 8a3ib8(s-dused by total internal reflection, which reflects most of the light that falls onto a cut diamond out of the face we see. Fake gems, called 'paste', are often used in jewellery because they are cheaper. However, paste gems sparkle much less than real diamonds.hja-w81ybc8( x0l 3 s iws5 dahm)yb/j

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?

  In a Young's double-slit experiment, the spacing of the doubl7sk((1ywvgek am) yl (e 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 $s$ ?

  The double-slit equation describes thy0xk:koqia5m3 )(caf e relationship between the separation distance of the fringes on the screen, s, the di(k:o)qkf305 ca ayx imstance 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?

  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 two waves. One wave is emitted w/0/hmo ,1ad 3zgoq7ws 6zbox from source $s_{1}$ 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 double slit interfgh 240b(dditdupxz ,)(u, qzl erence experiment is conducted using monochromatic light of wavelengtptqx(,l ) , u42bgz0hzddi (udh $\lambda$. 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?

  A monochromatic laser beam is shone i+ 1-i0+egeelh*xc)*d a fopu dnto the surface of a tank filled with water. The effects on the laser beam due to the wad eei * 0e +h1uaxp)flco+d-g*ter are observed.

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

  When does diffractionlr;3h- k+h bwx jhnb9;: 6umyd occur?

  Which phrase correctly completes the following sentensd qu;.+b (nge4u0es yce?

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

  The diagram shows a wave approaching a 7kmgcwzkx370 p6*qwfn aperture.


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

  Young's double-slit experiment is setup as shown,f: 9 xuu4zx8gr*u;sioxt*0rn including a monochromatic source, a single slit, a double slit and a screen. What is the purpose ofu*nriuu;8 0*: x r9gx4xtfosz the single slit in this experiment?

  $\mathrm{K}$ 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?

  The effect of a double slit on monochromatic light is observed by the set up 2ik79 rmxp6ga in the diagram bgkimrpa792 x6elow.



Interference fringes are seen on the screen.

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

  When moving from material *wp;j7gup03ty1j8tj wnu1cw 8ni 7o sa) ,aez$A$ 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?

  This diagram below shows two apertures through which planar waveia)()7pagx:wqx ac x )liup.oskh(1ps;69b ks are passed as they are moving to the left. The wavefronts show crests moving in phase. Given this information, at which point will the :)k1(apki6g(9axwps.oupx7x) chai)bs l; qamplitude of the waves be a minimum?



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

  Which property of a wave does not cha.;d8hkwi ialsams( 6h*/ ukb:nge as a result of refraction?

  The diagram below shows an arrangement umcyek y.x/,9d sed to investigate double slit interference using microwav c,.m/e9kyxy des.



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.

  Which row correctly desm,(ys)drr9mcal;7f ;yg t lv-cribes the conditions for constructive and destructive interf; sm( t;al)7g,yyr-rm fl9 vcderence in a double-slit diffraction pattern?

  Which image shows the correct ray diagram fjre od9j57y o29kdk(s or light passing from air into water? 7jeookddk9 5 y(sjr92

  Which of the following images shown below best represents the p /iv88hj/x zr+9bp)e isjjll* vi(t2 wath of visible light travelis9rej8i*viztpx+ jb/ vw8i/l2j l h()ng through a glass prism?

  A ray of light is incident on a materi87 b m8 yxazva5dzbu(/al made from three layers, each having a different optical density, so that in each vzy 88b/ uz5a mx(d7ablayer the light 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?

  Identical waves that begin propagation at the same - mni/rp) e1ojtime leave from two different sources and arrive at the same point em1jr)-in p/opoint $X$. 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 $X$ ?

  A student is investigating th9 )t 6n/sdbavle interference of waves. They set up coherent waves produced dv l69ab/sn)t at points $\mathrm{S}$ 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?

  When a light ray enters a denser medium and re :v6p/+t ltazrfracts, some of the characteristics of the wave will change. Which of the following options is correct about thi vla:ztr+t p/6s change?

  Which of the following options will alter the la./ln 9zpesiy33/f41( r cga1dtp s pfrequency of a wave?

  Two waves from individual point sources meet at a/ ;4 taebgoha;lp)3xek-1ska point $X$. Which of the following conditions is necessary for stable interference pattern to be observed at point $X$ ?

  Ray diagrams can be used to shsy,.i; xk/) :,n 1awg fvwqwprow the reflection, refraction and transmission of light at the boundar 1rw. f,sqvw/;,wkg a:xpn yi)y between media.


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

  Our fingerprints are made up of a series of ridge: 5rwl:v1in i drzee-,2xu x)es on the end of the finger. These ridges can be 'read' by electuzx-1reie, 2n ) :vrx:lw5di eronic 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?