Lens and Optics Quiz

What is the principal axis of a lens?

• The line perpendicular to the lens surface at the principal focus

• The line running through the center of the lens and perpendicular to the lens axis

• The line running through the center of the lens and parallel to the lens axis

• The line connecting the two principal foci of the lens

What happens when parallel light rays pass through a convex lens?

• They diverge away from the principal focus

• They continue to travel parallel without converging or diverging

• They are absorbed by the lens material

• They converge at a point called the principal focus or focal point

How is the power (P) of a lens measured?

• In meters (m)

• In centimeters (cm)

• In dioptres (D)

• In inches (in)

If a lens has a power of 2 dioptres, what is its focal length?

• 0.5 meters

• 2 meters

• 0.2 meters

• 5 meters

Which statement is true regarding the refraction of light through a lens?

• Light is refracted only once at the lens axis

• Light is refracted twice, once as it enters and once as it leaves the lens

• Light is refracted multiple times within the lens

• Light is not refracted but reflected by the lens

What are ray diagrams used for in the context of lenses?

• To determine the focal length of a lens

• To find the position and size of the image formed by a lens

• To measure the actual size of an object

• To calculate the intensity of light through a lens

What is the characteristic of the image formed by a lens when the object is placed at 2F?

• Real, Inverted, Magnified

• Real, Inverted, Same size as object

• Virtual, Right way up, Magnified

• Only appears at infinity

If an image formed by a lens is on the opposite side of the lens to the object and is said to be real, what does this imply?

• It can be projected onto a screen

• It is always magnified

• It is always diminished

• It cannot be projected onto a screen

What is the characteristic of the image when the object is placed at a distance less than the focal length (F) from the lens?

• Real, Inverted, Diminished

• Real, Inverted, Same size as object

• Virtual, Right way up, Magnified

• Only appears at infinity