Physics Class: Light - Reflection and Refraction

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Questions and Answers

What type of lens is described if its power is -2.0 D?

Cylindrical lens

Concave lens (correct)

Bifocal lens

Convex lens

If an object 5 cm tall is placed 25 cm from a converging lens with a focal length of 10 cm, what is the nature of the image formed?

Real and inverted (correct)

Virtual and inverted

Real and upright

Virtual and upright

How far is an object placed from a concave lens if it forms an image 10 cm from the lens, if the lens has a focal length of 15 cm?

15 cm

20 cm

5 cm

30 cm (correct)

What size and nature of the image is formed when an object of height 5 cm is placed 20 cm in front of a convex mirror with a radius of curvature of 30 cm?

3.0 cm, virtual Signup and view all the answers

What happens to light when it moves from one transparent medium to another?

It changes its direction. Signup and view all the answers

What is the focal length of a convex mirror with a radius of curvature of 32 cm?

16 cm Signup and view all the answers

What observation suggests that the bottom of a pond appears raised?

Light bends as it enters a different medium. Signup and view all the answers

When a pencil is half immersed in water, what contributes to the illusion of it being displaced?

Different angles of light create a visual effect. Signup and view all the answers

Which liquid would likely show a different extent of displacement for a pencil submerged in it?

Kerosene Signup and view all the answers

What happens to the appearance of letters when viewed through a glass slab?

They appear raised. Signup and view all the answers

Which of the following can be a consequence of light traveling through different media?

Direction of light can change. Signup and view all the answers

If a concave mirror produces a three-times magnified real image of an object placed at 10 cm, where is the image located?

At 30 cm from the mirror. Signup and view all the answers

What happens to paper when sunlight is converged by a concave mirror?

It ignites and may catch fire. Signup and view all the answers

What is the point at which reflected rays from a concave mirror intersect called?

The principal focus Signup and view all the answers

What is the nature of the image formed by a convex lens when the object is placed at infinity?

Real and inverted Signup and view all the answers

What is the role of the principal axis in relation to a concave mirror?

It is the axis normal to the mirror's surface. Signup and view all the answers

Where is the image formed when the object is placed between F1 and 2F1 in a convex lens setup?

Between F2 and 2F2 Signup and view all the answers

How is the focal length of a concave mirror approximately determined?

By locating the spot where light converges on a paper. Signup and view all the answers

What happens to the size of the image when the object is moved further away from a concave lens?

The image size decreases Signup and view all the answers

What is the main reason for the burning of paper when using a concave mirror to concentrate sunlight?

The concentrated light generates heat. Signup and view all the answers

When an object is placed at 2F1 in front of a convex lens, what is the relative size of the image formed?

Same size Signup and view all the answers

What is indicated if a concave mirror reflects rays of light that are parallel to the principal axis?

They converge at the focal point. Signup and view all the answers

What type of image is formed by a concave lens when observing an object such as a candle?

Virtual and erect Signup and view all the answers

What can be inferred if the bright spot of light appears closer to the mirror than expected?

The focal length is shorter than measured. Signup and view all the answers

If an object is placed at the focus F1 of a convex lens, what occurs to the size of the image?

The image becomes infinitely large Signup and view all the answers

What would happen if a convex mirror was used instead of a concave mirror in the same setup with sunlight?

Light would diverge and spread out. Signup and view all the answers

For an object placed beyond 2F1 of a convex lens, what is the nature of the image formed?

Real and inverted Signup and view all the answers

When observing through a concave lens, what is the position of the image compared to the object?

On the same side of the lens as the object Signup and view all the answers

What does the lens formula relate?

Object distance, image distance, and focal length Signup and view all the answers

Given a concave lens with a focal length of -15 cm, what is the sign of the image distance when forming a virtual image?

Negative Signup and view all the answers

How is the magnification 'm' calculated using object distance 'u' and image distance 'v'?

m = v / u Signup and view all the answers

If an object is placed 30 cm to the left of a concave lens producing a virtual image at -10 cm, what is the correct object distance 'u'?

-30 cm Signup and view all the answers

What type of image does a concave lens always form?

Virtual and erect Signup and view all the answers

What does a positive magnification value indicate about an image?

The image is virtual and erect Signup and view all the answers

What is the magnification produced by an image distance of -10 cm and an object distance of -30 cm?

0.33 Signup and view all the answers

Why must care be taken with the signs of different quantities in lens calculations?

To comply with common conventions in physics Signup and view all the answers

What does 1 dioptre of the power of a lens represent?

The reciprocal of the focal length in meters Signup and view all the answers

Where is the needle placed in front of a convex lens if the image formed is real, inverted, and equal in size to the object, given that the image distance is 50 cm?

100 cm from the lens Signup and view all the answers

What is the power of a concave lens with a focal length of 2 meters?

-2 dioptres Signup and view all the answers

What does the magnification produced by a spherical mirror represent?

The ratio of the height of the image to the height of the object Signup and view all the answers

When light travels from a denser medium to a rarer medium, how does it behave?

Bends away from the normal Signup and view all the answers

What determines the refractive index of a medium?

The ratio of the speed of light in vacuum to that in the medium Signup and view all the answers

What is the relationship between the focal length of a spherical mirror and its radius of curvature?

Focal length is equal to half the radius of curvature Signup and view all the answers

What occurs at both air-glass and glass-air interfaces in a rectangular glass slab?

Refraction takes place at both interfaces Signup and view all the answers

Study Notes

Light - Reflection and Refraction

Light travels in straight lines in a uniform medium
Things become visible when light is reflected off them and received by the eyes
Reflection is the bouncing of light off a surface
Reflection obeys the laws of reflection: -The angle of incidence is equal to the angle of reflection. -The incident ray, the normal to the mirror at the point of incidence, and the reflected ray all lie in the same plane.
Spherical mirrors are mirrors with curved surfaces, either concave or convex.

Spherical Mirrors

Concave -Reflecting surface curves inwards -Focuses light -Forms real or virtual images; erect or inverted, depending on the position of the object -Used in torches, headlights, and shaving mirrors
Convex -Reflecting surface curves outwards -Diverges light -Forms only virtual, erect and diminished images -Used in rearview mirrors

Image Formation by Spherical Mirrors

Object position affects the nature, position, and size of the image -Table of image position, nature and size for both Concave and Convex mirrors
Ray diagrams are used to show image formation
Key rays are used to construct ray diagrams: -A ray parallel to the principal axis, after reflection, will pass through the principal focus (or appear to diverge from it) -A ray passing through the centre of curvature is reflected back along the same path -A ray passing through the principal focus, after reflection, will emerge parallel to the principal axis

Refraction of Light

Light bends when it passes from one transparent medium to another. This is called refraction
Refraction happens because light travels at different speeds in different media
Refractive index relates speed of light in a vacuum to its speed in a medium; larger refractive index means light travels slower in that medium.

Refraction through a Rectangular Glass Slab

Light ray bends as it enters and exits the slab; emerges parallel to the original ray, but offset.

Lenses

Transparent material with at least one curved surface
Converging (convex) focused light rays - images can be real or virtual
Diverging (concave) spread light rays - only virtual images

Image Formation by Lenses

Position of the object affects the characteristics of the image formed
- Table depicting image characteristics for various object positions for both Concave and Convex
Ray diagrams are used to show image formation
Key rays used to construct ray diagrams: -A ray parallel to the principal axis, after refraction, passes through (or appears to diverge from) the focus -A ray passing through the optical centre passes undeflected -A ray passing through the focal point emerges parallel to the principal axis
Magnification = image height / object height = image distance / object distance

Power of a Lens

Power is the reciprocal of the focal length (measured in diopters)
Convex lenses have positive power
Concave lenses have negative power

Sign Conventions

Coordinate system for object and image distances is used
Distances to the right of the optical centre are positive
Distances to the left are negative
Distances above the principal axis are positive
Distances below are negative

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Description

This quiz covers the concepts of light reflection and refraction, specifically focusing on spherical mirrors. Learn about the laws of reflection, properties of concave and convex mirrors, and how images are formed. Test your understanding and application of these principles in real-world scenarios.