Refraction and Lenses Practice Test

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• Using the thin-lens formula 1/f = (n - 1)(1/R1 - 1/R2) for a symmetric bi-convex lens with R1 = +12 cm, R2 = -12 cm, n = 1.50, what is the focal length f?
• What do n1 and n2 denote?
• Two lenses in contact: f1 = +40 cm and f2 = +20 cm. What is f_eq?
• Which statement correctly describes a convex lens?
• A convex lens is thicker in the middle than at the edges, and causes light rays to ______.
• A concave lens typically forms what kind of image for a real object?
• Total internal reflection condition.
• Which statement describes the image produced by a concave lens?
• In dispersion of white light by a prism, which color is bent the least?
• Which ray emerges parallel to the axis after passing through the focal point on the object side of a convex lens?
• True or false: If a bar magnet is cut in half, each piece remains magnetized with both a north and a south pole.
• Which statement best describes Cleo's mistake about light entering water from air?
• A prism disperses white light into a spectrum.
• Which statement about Earth's inner core is true?
• Which statement describes the interaction of light with materials in general?
• The image formed by a concave lens is always virtual.
• What happens when light from the Sun passes through any type of matter?
• Which statement describes the core's composition?
• Which statement about Earth's core composition is true?
• If a medium has index n = 1.50, the speed of light in that medium is approximately what fraction of c?
• The optical power of a lens with focal length f = +25 cm is:
• Which object is most likely to be transparent, allowing light to pass through?
• The cornea provides most of the eye's focusing power; the lens can adjust focus.
• A light ray goes from air into water with incidence 60 degrees; refracted angle is approximately?
• When light passes from air into a denser medium, the refracted ray bends toward the normal.
• Isaac Newton believed that light was made of:
• Where is the real image located when a convex lens forms a real image?
• Which elements must be included when drawing ray diagrams?
• A real image produced by a convex lens can be projected onto a screen.
• Which statement best describes what happens when light travels from air into water at an angle?
• Which color of white light bends the most when refracted by a prism?
• Which statement about magnetic poles is true?
• What is the effect of rubbing a magnet along a needle multiple times?
• In a magnetic field, outside a magnet, the field lines run from the ______ pole to the ______ pole.
• Which statement describes the sign of image distance v for a real image formed on the opposite side of a lens using the standard Cartesian convention?
• Which describes an image that can be produced by a concave lens?
• Prisms separate white light by wavelength. Which is the type of light they separate?
• A light ray moves from air into water (n1 < n2). Will the angle of refraction be larger or smaller than the angle of incidence?
• Where is the focal point for a concave lens located?
• Which statement describes the mechanism generating Earth's magnetic field?
• A ray parallel to the axis passes through the focal point on the opposite side after refraction by a convex lens. This is a property of which lens type?
• What is the sign of the focal length for a diverging lens?
• A diverging lens (negative focal length) typically forms what type of image for a distant object?
• In Snell's law, theta1 and theta2 represent?
• Which statement explains why the paper clip falls away when the external magnet is removed in the nail-paper clip scenario?
• If light passes from air into a medium with n = 1.40 at incidence 30°, what is the approximate refracted angle?
• The critical angle for water-to-air is about 48.6°. If the incident angle is 55°, what happens?
• A ray travels from glass (n ≈ 1.52) into air. Relative to the normal, does the refracted ray bend toward or away from the normal?
• Define refractive index in terms of speed of light.
• A light ray in water hits the water–air interface at 60° to the normal. Will it refract or total internal reflect?
• What focal length corresponds to a lens power of +4.0 diopters?
• Which of these would correct Sayid's error?
• For a lens with a negative focal length, what type of lens is it most likely?
• Two bar magnets are brought near each other with like poles facing. What will happen?
• For a simple magnifier, the angular magnification M ≈ 25 cm / f. If f = 5 cm, what is M?
• If focal length halves from 8 cm to 4 cm, what happens to the angular magnification M ≈ 25 / f?
• Which type of lens can form an image that may be real or virtual?
• Real images produced by lenses can be:
• When light passes from air into a denser medium, it bends toward which direction relative to the normal?
• Can a virtual image produced by a lens be projected onto a screen?
• If an object is located beyond the focal length of a convex lens, the image formed is real and located on the opposite side. True or false?
• If two magnets align with the north of one facing the south of the other, what will happen to their distance?
• The direction of bending when light passes from air into water is toward the normal. True or false?
• Total internal reflection occurs when?
• A ray parallel to the principal axis enters a convex lens of focal length 15 cm. After refraction, the ray travels toward which point?
• A convex lens can form which types of images depending on the object distance?
• The near point of the human eye is approximately 25 cm.
• Which statement about Earth's magnetic field is correct?
• According to Christiaan Huygens, what was light made of?
• In a digital camera, the image detected by the sensor forms at the location where light rays coming from the object converge.
• Which object absorbs the most visible light?
• Which description best matches Earth's magnetic field lines?
• For light entering from air into a higher-index medium, the refracted ray bends toward the normal.
• Which type of lens always forms a virtual, upright image, regardless of object distance?
• When light enters a glass slab with parallel faces at any angle, how does the emergent ray compare to the incident ray in angle relative to the normal?
• In Snell's law, which angle is theta2?
• The object made of glass that disperses white light into a spectrum is called what?
• Which type of image cannot be projected and appears to originate from the light rays?
• Two lenses in contact have focal lengths f1 = +40 cm and f2 = +40 cm. What is the equivalent focal length f_eq?
• Which lens always forms virtual images for any object position?
• Which statement best explains a difference between the interaction of light with clear glass and the interaction of light with silver metal?
• If a bar magnet is cut in half, what is true about the pieces?
• An air-to-water boundary: does a ray bend toward or away from the normal when entering the water?
• If the object is located at the focal point of a convex lens, the emergent rays are?
• Which statement about field lines and geographic poles is true?
• Which lens corrects nearsightedness?
• A ray enters a glass with n ≈ 1.52 from air at incidence 60°. What is the refracted angle approximately?
• A glass slab with parallel faces: does the emergent ray make the same angle with the normal as the incident ray?
• Which statement describes the image produced by a concave lens?
• A concave lens always produces which type of image?
• Which observation best illustrates that light behaves like particles?
• If the object is effectively at infinity, where is the image formed by a lens with focal length f?
• A ray from air into water at an incidence of 40° bends toward the normal.
• Why does green light slow down more than orange light when passing through an object?
• Lines of force drawn around a magnet illustrate the magnetic ______.
• Which element is a main component of steel?
• Opposite poles of two magnets attract when brought near one another. Which statement is true?
• Which object would most likely allow light to pass through clearly?
• The comparison between glass and silver metal shows that glass is transparent and metal is opaque.
• In a convex lens, a ray that travels parallel to the principal axis should bend toward the axis and pass through which point on the opposite side?
• Which element is magnetic?
• Which statement describes a property of magnets?
• What is the sign of the focal length for a converging lens?
• A disc magnet has its north and south poles on its faces. To achieve levitation of a model maglev train, how should the magnets be arranged on the train and track?
• In a ray diagram, the three rays typically start from:
• A person with myopia requires corrective lenses of power −2.00 D. What is the focal length of these glasses?
• Which statement describes the states of Earth's inner and outer cores?
• After twenty minutes under a lamp, which surface will feel warmer?
• Which lens corrects farsightedness?
• Which ray emerges parallel to the axis after refraction from a convex lens?
• What is true about the central ray (the one that passes through the center of the lens) in a typical ray diagram?
• A concave lens is thinner in the middle than at the edges, and causes light rays to ______.
• Which statement about the Moon's core is accurate?
• In ray tracing for a thin lens, which ray goes through the optical center without bending?
• What happens to light speed when light passes from air into a denser medium such as glass?
• Which phenomenon occurs when light strikes a flat mirror?
• What term describes the bending of light as it moves from air into glass?
• Joe follows the procedure below to make a compass. What is the purpose of step 1?
• What is the approximate speed of light in space?
• If the speed of light increases, which statement about frequency is true?
• Two thin lenses in contact have focal lengths +20 cm and +10 cm. The combined focal length f_eq is approximately:
• Under which color of light will plants be least likely to make food?
• Compared to the speed of light in air, the speed of light in water is ______.
• Which device is used to produce a converging image by directing rays to a single point?
• Which statement correctly describes a concave lens?
• Two thin lenses in contact with f1 = +40 cm and f2 = +20 cm yield an effective focal length of approximately:
• Which object is least likely to allow light to pass through it?
• Light moving from a denser to a less dense medium bends in which direction relative to the normal?
• Which mechanism explains the existence of Earth's magnetic field?
• Dispersion through a prism causes different wavelengths to refract by different amounts.
• At the critical angle for a water-to-air boundary (theta_c ≈ 48.6°), what happens to the refracted ray when the incident angle equals theta_c?
• For a distant object, a converging lens forms an image at which location?
• If the refractive index increases while the light frequency remains constant, what happens to the wavelength in the medium?
• When light moves from a less dense medium into a denser medium, it is refracted ______ the normal.
• Which statement about Earth's outer core is true?
• In a concave-lens diagram of a plastic bottle, which statement is true about the image size?
• If the ends X and Y of two magnets have field lines such that lines leave X and enter Y, what are the poles of X and Y?
• Total internal reflection occurs when a ray moves from a denser to a rarer medium and the incident angle exceeds the critical angle.
• When parallel light rays exit a concave lens, the light rays ____.
• Which equation represents Snell's law?
• Which process in the outer core contributes to Earth's magnetic field?
• An object made of which material is likely to be attracted to a magnet?
• A concave lens with focal length −20 cm forms what kind of image for any object distance?
• A ray aimed at the focal point on the object side of a convex lens emerges on the other side parallel to the axis. This statement is?
• Juan created a chart to help him study for a test. Which headings best complete the chart?
• Which type of lens can produce a real image?
• In general, a diverging lens forms what type of image for a real object placed in front of it?
• If a lens forms a real image on the opposite side of the lens from the object, what is the sign of the image distance v?
• A real image formed by a convex lens is which of the following?
• When parallel light rays exit a concave lens, they ______.
• What is the approximate critical angle for total internal reflection when light travels from glass (n ≈ 1.50) to air (n ≈ 1.00)?
• Which lens is thinner in the center than at the edges?
• Which best describes the type of lens that would help someone who is nearsighted?
• A telescope is adjusted so that the final image is at infinity. What is the approximate separation between the objective and eyepiece?
• To correct Akio's mistake, what adjustment should be made?
• An incident ray in air strikes water at 30° to the normal. The refracted angle in water is approximately?
• When a second south pole is brought near the south pole of a magnet, how are the field lines affected?
• The ends of a magnet where the forces are strongest are called magnetic ______.
• What best describes the outer core's state?
• For a symmetric bi-convex lens with fixed radii, increasing the refractive index n of the lens material will cause the focal length to
• Which statement correctly describes the direction of magnetic field lines around a magnet?
• The far point of a normal, relaxed eye is at infinity. True or false?
• A real image formed by a lens of a diamond ring is which of the following?
• After magnetizing the needle and placing it on a cork floating in water, what direction will the needle most likely point?
• When parallel light rays exit a convex lens, they ______.
• A converging lens can form a real image of a distant object.
• Write the thin lens equation.
• When light rays exit a lens, which description best describes their direction?
• In a simple refracting telescope, the magnification is approximately M ≈ f_o / f_e. If f_o = 300 cm and f_e = 25 cm, what is M?
• Which statement correctly compares the speed of light?
• Magnification in a thin lens and what its sign indicates.
• Which term describes the change in direction of light as it passes from one medium to another, such as from air into glass?
• Where are the north and south poles located on a disc magnet?
• If an object is placed far away from a convex lens, the image formed is real.
• Which lens produces a real image when the object is placed beyond the focal length?
• Prisms separate white light by wavelength. Which term best describes this process?
• Which statement is true about magnetic field lines relative to geographic poles?
• If a thin lens in air has a positive focal length, what does this say about the lens type?
• Jill uses a magnet to pick up a nail. Then she touches the nail to a paper clip and picks up the paper clip. What will most likely happen when she pulls the magnet away from the nail?
• To triple the telescope magnification M ≈ f_o / f_e while keeping f_e constant, what should you do to f_o?
• Which of the following is a magnetic material?
• What is the power of a lens with focal length −0.50 meters?
• What is Roshan's error in the ray diagram?
• Decreasing the focal length of a convex lens, all else equal, would:
• After the 1600s, observations of light being refracted caused scientists to begin believing that light acted as:
• Which item reflects light with the highest frequency?
• Which statement describes a convex lens?
• The thin-lens formula for a thin lens in air is 1/f = (n - 1)(1/R1 - 1/R2). For a symmetric bi-convex lens with R1 = +12 cm and R2 = -12 cm and n = 1.50, what is f?
• Which property did Janssen most likely believe about light during the invention period?
• For a convex lens with focal length f, if the object is placed at u = -2f, where is the real image formed and what is its orientation?
• Which lens can form a real, inverted image of a distant object on a screen?
• A diverging lens normally forms what type of image?