PHYS II Final Exam

What are the two requirements for light to undergo Total Internal Reflection (TIR)?

• N(incident, 1) must be greater than N(refracted, 2)

• The angle of incidence must be greater than the critical angle

How does the trajectory of light change when it moves from a lower N to a higher N?

It slows down- thereby bending TOWARDS the normal line.

How does the trajectory of light change when it moves from a higher N to a lower N?

It speeds up- thereby bending AWAY from the normal line.

What is a virtual image?

No light rays actually pass through the image point, and create an UPRIGHT image.

They only appear to be coming from it and doesn’t actually exist in physical space, despite having a definite position and size.

CANNOT be projected onto a screen.

What is a real image?

An INVERTED image formed when light rays converge and pass through a point in space, producing a definite and tangible representation of an object.

CAN be projected onto a screen.

If an object is placed in front of a CONCAVE MIRROR, and Do > R (radius of curvature), what image is formed?

A real (and thereby inverted), and REDUCED image.

If an object is placed in front of a CONCAVE MIRROR, and R > Do > f, what image is formed?

A real (and thereby inverted), and ENLARGED image.

If an object is placed in front of a CONCAVE MIRROR, and f > Do > 0, what image is formed?

A virtual (and therefore upright), and enlarged image.

What is the ONLY kind of image a CONVEX MIRROR ever produce?

A virtual (and therefore upright), and reduced image.

If an object is placed in front of a CONVERGING LENS, and Do > R, what image is formed?

A real (and thereby inverted), and reduced image.

If an object is placed in front of a CONVERGING LENS, and R > Do > f, what image is formed?

A real (and therefore inverted), and enlarged image.

If an object is placed in front of a CONVERGING LENS, and f > Do > 0, what image is formed?

A virtual (and therefore upright), and enlarged image.

What is the ONLY kind of image a DIVERGING LENS can ever produce?

A virtual (and therefore upright), and reduced image.

List the sign conventions are for MIRRORS.

Image distance is POSITIVE to the LEFT (aka, the same side as the object) of the mirror and NEGATIVE to the RIGHT.

Object distance is always POSITIVE in front of the mirror / lens.

CONCAVE mirrors have a POSITIVE focal length, while CONVEX mirrors have a NEGATIVE focal length.

List the sign conventions are for LENSES.

Image distance is NEGATIVE to the LEFT (aka, the same side as the object) of the lens, and POSITIVE to the RIGHT.

f is POSITIVE for CONVERGING LENSES, and NEGATIVE for DIVERGING LENSES

What is required for electric charge to be transferred by rubbing?

Only INSULATORS can be charged in this way, and the two materials must be DIFFERENT.

What is required for electric charge to be transferred by touching?

Only CONDUCTORS can be charged in this way.

What is charging by induction?

Charging an object without touching it to another charged object. (Likely, via polarization)