Quick Review Flashcards - Click to flip and test your knowledge!
Question
What term describes the return of light into the same medium after striking a surface?
Answer
Reflection
Question
Light bodies that emit light by themselves are known as _____ bodies.
Answer
Luminous
Question
Which type of reflection occurs when a parallel beam of light falls on a smooth and polished surface, reflecting in a single fixed direction?
Answer
Regular reflection
Question
Why can an object be seen from anywhere when light undergoes irregular reflection?
Answer
The reflected light spreads over a wide area in different directions.
Question
The light ray striking a reflecting surface is called the _____.
Answer
Incident ray
Question
Definition: Normal
Answer
The perpendicular drawn to the reflecting surface at the point of incidence.
Question
What is the angle of incidence $i$?
Answer
The angle which the incident ray makes with the normal at the point of incidence.
Question
First Law of Reflection: The angle of incidence $i$ is equal to the _____.
Answer
Angle of reflection $r$
Question
Second Law of Reflection: The incident ray, the reflected ray, and the normal at the point of incidence all lie in the _____.
Answer
Same plane
Question
If a ray is incident normally on a plane mirror (angle $i = 0^{\circ}$), what is the angle of reflection $r$?
Answer
$0^{\circ}$
Question
An image that can be obtained on a screen is called a _____ image.
Answer
Real
Question
A virtual image is formed when light rays after reflection do not actually intersect but appear to _____ from a point.
Answer
Diverge
Question
How does the size of an image formed by a plane mirror relate to the size of the object?
Answer
They are of the same size.
Question
Where is the image formed by a plane mirror situated in relation to the mirror?
Answer
At the same perpendicular distance behind the mirror as the object is in front of it.
Question
The interchange of the left and right sides in the image of an object in a plane mirror is called _____.
Answer
Lateral inversion
Question
Why do the letters on the front of an ambulance appear as 'ECNALUBMA'?
Answer
So the driver ahead sees the word laterally inverted as 'AMBULANCE' in their rear-view mirror.
Question
If an object is moved a distance $d$ towards a plane mirror, by what distance does the separation between the object and image decrease?
Answer
$2d$
Question
Formula: Number of images ($n$) for two mirrors at angle $\theta$ when $360/\theta$ is even.
Answer
$n = \frac{360^{\circ}}{\theta} - 1$
Question
How many images are formed when two plane mirrors are kept parallel to each other?
Answer
Infinite
Question
If two plane mirrors are perpendicular to each other ($\theta = 90^{\circ}$), how many images are formed?
Answer
3
Question
In which instrument are two parallel plane mirrors inclined at $45^{\circ}$ with vertical walls used?
Answer
Periscope
Question
Which device uses three plane mirrors inclined at $60^{\circ}$ to create hexagonal patterns?
Answer
Kaleidoscope
Question
A reflecting surface which is part of a hollow sphere is called a _____.
Answer
Spherical mirror
Question
Which type of spherical mirror is made by silvering the outer surface so reflection occurs from the hollow surface?
Answer
Concave mirror
Question
Definition: Pole ($P$) of a spherical mirror
Answer
The geometric centre of the spherical reflecting surface.
Question
The centre of the sphere of which a spherical mirror is a part is called the _____.
Answer
Centre of curvature ($C$)
Question
What is the principal axis of a spherical mirror?
Answer
The straight line joining the pole to its centre of curvature.
Question
The focus of a concave mirror is the point on the principal axis where rays incident parallel to the axis _____ after reflection.
Answer
Pass (or actually meet)
Question
The focus of a convex mirror is a point from which rays incident parallel to the principal axis appear to _____.
Answer
Diverge
Question
What is the focal length $f$ of a spherical mirror?
Answer
The distance from the pole $P$ to the focus $F$.
Question
Relationship: Focal length $f$ and Radius of curvature $R$
Answer
$f = \frac{1}{2} R$
Question
A ray passing through the centre of curvature of a spherical mirror is reflected _____.
Answer
Back along its own path
Question
A ray incident parallel to the principal axis of a concave mirror passes through the _____ after reflection.
Answer
Focus ($F$)
Question
A ray incident through the focus of a concave mirror becomes _____ to the principal axis after reflection.
Answer
Parallel
Question
What are the nature, position, and size of the image formed by a concave mirror when the object is at infinity?
Answer
Real, inverted, highly diminished, and at the focus.
Question
Where must an object be placed in front of a concave mirror to obtain an image of the same size?
Answer
At the centre of curvature ($C$)
Question
When an object is placed between the focus and the pole of a concave mirror, what is the nature of the image?
Answer
Virtual, upright, and magnified.
Question
Where is the image formed by a concave mirror when the object is at the focus $F$?
Answer
At infinity
Question
A convex mirror always forms a virtual, upright, and _____ image.
Answer
Diminished
Question
Mirror Formula: Relationship between $u$, $v$, and $f$
Answer
$\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$
Question
In sign convention, distances opposite to the direction of incident light are considered _____.
Answer
Negative
Question
Why is the focal length of a concave mirror considered negative?
Answer
The focus is measured opposite to the direction of incident rays from the pole.
Question
Definition: Linear magnification ($m$)
Answer
The ratio of the length of the image ($I$) to the length of the object ($O$).
Question
Magnification formula in terms of $v$ and $u$
Answer
$m = -\frac{v}{u}$
Question
What does a negative magnification ($m$) indicate about an image?
Answer
The image is real and inverted.
Question
Which mirror is used as a shaving mirror to see a magnified image of the face?
Answer
Concave mirror
Question
Why is a concave mirror used as a reflector in a torch?
Answer
When the bulb is at the focus, it produces a parallel beam of light.
Question
Why is a convex mirror preferred as a rear-view mirror in vehicles?
Answer
It provides a wider field of view and always forms an erect image.
Question
Which type of mirror is used in street lamps to diverge light over a larger area?
Answer
Convex mirror
Question
How can you distinguish a plane mirror from others without touching if the image is upright and of the same size?
Answer
It is a plane mirror.
Question
If the image is upright, magnified, and increases in size as the mirror moves away, the mirror is _____.
Answer
Concave
Question
If the image is upright, diminished, and decreases in size as the mirror moves away, the mirror is _____.
Answer
Convex
Question
In multiple images formed by a thick plane mirror silvered at the back, which image is the brightest?
Answer
The second image
Question
The focal plane is a plane passing through the focus and _____ to the principal axis.
Answer
Normal (or perpendicular)
Question
What is the value of $u$ for an object placed $25\text{ cm}$ in front of a mirror according to sign convention?
Answer
$-25\text{ cm}$
Question
In which case is the magnification $m = +1$ for a spherical mirror?
Answer
This case is not possible for spherical mirrors (it is $1$ for a plane mirror).
Question
A doctor's head mirror uses a _____ mirror to focus a beam of light on the body part to be examined.
Answer
Concave
Question
Where does the image of an object at a 'very far distance' (but not infinity) form for a concave mirror?
Answer
In the focal plane
Question
What is the aperture of a spherical mirror?
Answer
The plane surface area of the mirror through which light rays enter and fall on the mirror.
Question
If $n = 360/\theta$ is odd and the object is placed symmetrically, what is the formula for the number of images?
Answer
$n = \frac{360^{\circ}}{\theta} - 1$