Light, Waves and Optics

Light, Waves and Optics

by Ronnie Lorilla

Reflection of light

​Reflection of waves

​Watch the video and notice the direction that the wave fronts are reflected by the straight solid boundary.

The reflection for a light ray is similar to that of a wave.

The angle of incidence is measured from the light ray to the normal line.

The angle of reflection is also measured the same.

​

Notice how the angle of incidence and the angle of refraction is labelled.

​

​It is according to the how the light ray travels.

​Refraction of waves

​To answer the next question, observe the how the wave fronts change direction, wavelength and speed as it passes through a medium of higher density.

​

​Note, the distance between the wave fronts is the wavelength of the wave.

Multiple Choice

Light travels in ___________ lines

• wavy

• bent

• straight

• backwards

Multiple Choice

what is the angle between the incident ray and the normal called as

• angle of incidence

• angle of reflection

• angle of convergent

• angle of divergent

Multiple Choice

IF THE ANGLE OF INCIDENCE IS 20 DEGREES, WHAT WILL BE THE VALUE OF ANGLE OF REFLECTION?

• 0

• 10

• 20

• 40

Multiple Choice

If the angle of incidence is 45 degree, what is the angle between the incident ray and reflecting surface

• 45

• 90

• 180

• none of the above

Multiple Choice

What is the line MN called in the given diagram
                               

• incident ray
• reflected ray
• reflecting surface
• normal

Reflection by plane mirror

Multiple Choice

Which statement is true for plane mirrors?

• They are flat, smooth surfaces that produce diffuse reflection.

• They are curved, smooth surfaces that produce diffuse reflection.

• They are flat, smooth surfaces that produce specular reflection.

• They are curved, smooth surfaces that produce specular reflection.

Multiple Select

The image formed in a plane mirror is

• real image

• the same size as the object​

• bigger than the object

• virtual image

• in front of the mirror.

Multiple Choice

The following are the image formed in plane mirror except....

• erect

• virtual

• same size

• inverted

Multiple Choice

The bouncing off of light rays from the surface of an object such as a mirror or other shiny surface is called:

• mirror

• laser

• reflection

• refraction

Multiple Choice

Law of reflection state that - The angle of incidence is .................. to the angle of reflection.

• equal

• double

• half

Multiple Choice

Which of these is the best reflector of light?

• shiny metal
• white paper
• carpet
• wood

Multiple Choice

Images produced by plane mirrors are real images.

• True

• False

Multiple Choice

If the man is 4 m from the mirror, his image is how far from the mirror?

• 2 m

• 4 m

• 8 m

Multiple Choice

According to laws of reflection,

• angle of incidence > angle of reflection

• angle of incidence < angle of reflection

• angle of incidence = angle of reflection

• both 1 and 2

Multiple Choice

What kind of light rays form a virtual image?

• converging rays

• diverging rays

• refracting rays

• diffracting rays

Multiple Choice

This image shows the reflected image of a word. It appears to be flipped. This phenomena is called......

• lateral inversion

• reflection

• incidence

• normal

• medial inversion

Multiple Choice

In plane mirrors, what is the equation relating the position of an object $$\left(x_o\right),$$ and the position of its image $$\left(x_i\right)$$ , with respect to the mirror?

• $$x_o=x_i$$  

• $$x_o=-x_i$$  

• $$-x_o=-x_i$$  

• $$x_o=2x_i$$  

Multiple Choice

Which statement is true for the normal in a ray diagram at the point where the light strikes?

• It is perpendicular to the surface

• It is parallel to the surface

Multiple Choice

In the ray diagram shown, find the angle of incidence of the second ray.

• $$5\degree$$  

• $$25\degree$$  

• $$35\degree$$  

• $$55\degree$$  

• undefined 

Multiple Choice

The image formed by a plane mirror is positioned _________ the mirror.

• above

• below

• in front of

• behind

Convex Lens Virtual image: 

An image that is upright.

Convex Lens: Real Image:

an image that can be “projected” 

(on a screen or on paper),

***always inverted!***

Multiple Choice

Convex mirror is also called as

• converging mirror

• diverging mirror

• plane mirror

• silver mirror

Multiple Choice

The relation between focal length and radius of curvature is

• R = 2f

• 1/f = 2R

• f = R/2

• R = 2/f

Multiple Choice

The point on the spherical mirror at the middle of the surface is called

• focus

• centre of curvature

• pole

• radius of curvature

Multiple Choice

A convex mirror has a focal length 12 cm. Then its radius of curvature is ........ cm

• 24

• 12

• 6

• 1.2

Multiple Choice

When the object is in between the centre of curvature (C) and focus (F) of a concave mirror, then the position of the image is ...........

• At focus

• At the centre of curvature

• at infinity

• beyond the centre of curvature

Multiple Choice

Which mirror is shown in the figure?

• convex mirror

• concave mirror

• plane mirror

• silver mirror

Multiple Choice

Mirror formula is defined as ........

• A

• B

• C

• D

Multiple Choice

When the object is at infinity, a point sized image is formed at ................ by the convex mirror

• focus behind the mirror

• focus in front of the mirror

• radius of curvature

• principal axis

Multiple Choice

The image formed by a concave mirror when the object is placed between the pole and the focus is ......

• virtual, erect and magnified

• virtual, erect and diminished

• real, inverted and magnified

• real, inverted and diminished

Multiple Choice

The angle of incidence of a ray of light passing through the centre of curvature of a concave mirror is ........... degree

• 105

• 180

• 90

• 0

Multiple Choice

Where will be the images of the Sun or the moon are formed by a concave mirror?

• Focus

• Pole

• centre of curvature

• beyond centre of curvature

Multiple Choice

What is the size of the image formed when an object is kept at the focus in front of concave mirror?

• enlarged

• diminished

• highly enlarged

• highly diminished

Multiple Choice

MCQ 08 If a capital letter R is seen in an ordinary mirror, what does it look like?

• A

• B

• C

• D

Multiple Choice

If the angle of incidence is 45 degree, what is the angle between the incident ray and reflecting surface

• 45

• 90

• 180

• none of the above

Multiple Choice

In the image, all the rays meet at F, What is F

• focal length

• focal point

• center of curvature

• reflection

Multiple Choice

What is an image called that forms when light rays actually meet

• virtual image

• real image

• diffuse reflection

• regular reflection

Multiple Choice

The two types of spherical mirrors are ...............

• flat and plane

• concave and plane

• convex and concave

• plane and rectangular

Multiple Choice

If 'R' is radius of curvature and 'f' is focal length of a spherical mirror then the correct relation between the two is

• R = f

• R = f/2

• f = 2R

• f = R/2

Multiple Choice

When distance of object from a mirror is gradually increased then image formed by it becomes inverted which was erect in the beginning. Which type of mirror is this ?

• Plane mirror

• Concave mirror

• Convex mirror

• none of the above

Multiple Choice

which of the following is not a property of the image formed by a [lane mirror?

• virtual and erect

• Object size = image size

• object distance = image distance

• Real and inverted

Multiple Choice

Which of the following is a concave mirror?

Multiple Choice

Four students A, B, C and D performed the experiment to determine the focal length of a concave mirror by obtaining the image of a distant tree on a screen. They measured the distances between the screen and the mirror as shown in the above figure.

The correct way of measuring accurate focal length of the mirror is

• A

• B

• C

• D

Multiple Select

In a concave mirror if the object is placed at the focal point, then the image is?

• never formed as the reflected light is parallel and they never meet

• inverted and at the focal point

• inverted and in-between the centre of curvature and the focal point

• inverted and before the focal point

Multiple Select

If the object is placed in-between the centre of curvature and the focal point in a concave mirror, then the image is?

• inverted and at the centre of curvature

• inverted and ahead of the centre of curvature

• inverted and before the centre of curvature

• inverted and in-between the centre of curvature and the focal point

Multiple Select

In a concave mirror if the object is placed ahead of the focal point, then the image is?

• formed magnified and behind the mirror

• diminished and behind the mirror

• inverted and at the centre of curvature

• inverted and at the focal point

Multiple Choice

• Size of image is larger.

• Size of image is farther.

• Size of image is the same.

• Size of image is smaller.

Multiple Choice

How many image characteristics do we report?

• 1

• 2

• 3

• 4

Multiple Choice

• Location of image is closer.

• Location of image is farther.

• Location of image is the same.

Multiple Choice

In a ray diagram, the image is drawn:

• wherever you want.

• on the right of the mirror.

• where the reflected rays cross.

• where any two rays cross.

Multiple Choice

Which one of the following is the image obtained by the plane mirror ?

Multiple Choice

Which number is seen by the observer ?

• 22

• 25

• 55

• 35

• 52

Multiple Choice

Point objects K L M N are placed in front of the plane mirror as shown in the figure. Which point(s) can be seen by the observer at point G ?

• K and M

• M and N

• K and L

• K, M and N

• M, N and L

Multiple Choice

Which picture represents what happens when light travels through a CONVERGING lens?

• A- left picture

• B - Right picture

Multiple Choice

what type of mirror is this

• concave

• convex

• translucent

• plane

Multiple Choice

Latha is observing her image in a plane mirror. The distance between the mirror and her image is 6 m. If she moves 2m towards the mirror then the distance between latha and her image will be

• 8 m

• 4 m

• 10 m

• 5 m

Multiple Choice

Images that can't be captured on a screen are called

• Real image

• Virtual image

• Proper image

• Imaginary image

Multiple Choice

Focus is situated behind the mirror of

• Concave mirror

• Convex mirror

• Both

• None

Multiple Select

Choose all the terms that are associated with Orientation of an image:

• Inverted

• Virtual

• Real

• Upright

Multiple Choice

When determining image location and size...

• look at what side of the mirror it's on.

• compare it to the object.

• divide the distance by the height.

Multiple Choice

What Type of image can be shown on a screen?

• Virtual

• Inverted

• Real

• Concave

Multiple Choice

The mirror shown here is:

• Plane

• Concave

• Convex

Multiple Choice

• Location of image is closer.

• Location of image is farther.

• Location of image is the same.

Multiple Choice

• Orientation of image is upright.

• Orientation of image is farther.

• Orientation of image is real.

• Orientation of image is inverted.

Multiple Choice

• Size of image is larger.

• Size of image is farther.

• Size of image is the same.

• Size of image is smaller.

Multiple Choice

• Type of image is real.

• Type of image is reversed.

• Type of image is the virtual.

• Type of image is smaller.

Multiple Choice

• This mirror is concave.

• This mirror is convex.

• This is a plane mirror.

Multiple Select

Check all the true statements:

• The image is inverted.

• The image is upright.

• The image is real.

• The image is virtual.

Multiple Choice

Concave mirrors cannot produce virtual images.

• True

• False

Multiple Choice

In a ray diagram, the rays start:

• at the mirror.

• at the bottom of the object.

• at F.

• at the top of the object.

Multiple Choice

In a ray diagram, the first ray that you draw goes:

Multiple Choice

In a ray diagram, the image is drawn:

• wherever you want.

• on the right of the mirror.

• where the reflected rays cross.

• where any two rays cross.

Vibrations & Waves

The period of a pendulum depends only on its length, mass has no effect.

Wave Calculations

Multiple Choice

What variable determines the length of a pendulum's period?

• pendulum mass

• pendulum length

• time

Multiple Choice

A wave has a frequency of 13.5 Hz and a speed of 42 m/s. What is the wavelength of the wave?

• 570 m

• 570 m/s

• 3.1 m

• 3.1 m/s

Multiple Choice

Which location represents the amplitude?

• f

• g

• h

• j

Multiple Choice

Which location represents the wavelength?

• f

• g

• h

• j

Multiple Choice

Both sound and light waves do not need a medium to travel through.

• true

• false

Multiple Choice

What's going on here?

• Reflection

• Refraction

Multiple Choice

In a vacuum or in air, all types of waves (RMIVUXG) travel at the same speed (speed of light)

• True

• False

Multiple Choice

What do you think happens when a ray of visible light enters water (for example)?

• Speeds up

• Slows down

• Nothing

Multiple Choice

What would you see after polarizer 2?

• Nothing because the vertical light can't fit through the horizontal opening

• Horizontal light because the vertical light gets reshaped

• Vertical light because it can just pass through because it's light

Multiple Choice

This image is representing what wave interaction?

• Refraction
• Diffraction
• Reflection
• Interference

Multiple Choice

What can you tell about this object's motion?

• Moving to the North (up).
• Moving to the South (down). 
• Moving to the West (left). 
• Moving to the East (right). 

Multiple Choice

What is this phenomenon called?

• Doppler Effect

• Diffraction

• Reflection

• Interference

Multiple Choice

Look at the picture. Who is experiencing a higher pitched sound?

• Observer A

• Observer B

• There's no difference

Multiple Choice

What can you tell about this object's motion?

• Moving to the North (up).
• Moving to the South (down). 
• Moving to the West (left). 
• Moving to the East (right). 

Multiple Choice

What best describes the doppler effect?

• An apparent change in frequency of a wave due to the relative motion between a wave source and an observer
• When sound changes pitch
• When light changes color
• An apparent change in the amplitude of a wave due to the relative motion between a wave source and an observer.

Multiple Choice

When an ambulance move TOWARD you it sounds ________ pitched. 

• high
• low
• medium

Multiple Choice

The Doppler effect is seen when a wave-making source moves toward an observer. 

• True
• False