Question 1

A telescope has an objective lens with a focal length of 90 cm and an eyepiece of focal length 3.0 cm. What is the angular magnification of the telescope?

Accepted Answer

The angular magnification of a telescope is given by the formula:

M = (-) fo / fe

where fo is the focal length of the objective lens and fe is the focal length of the eyepiece.

Substituting the values given, we get:

M = (-)90 cm / 3.0 cm

M = (-)30

The negative sign indicates that the image formed by the eyepiece is inverted compared to the object. Therefore, the angular magnification of the telescope is 30.

So, the best choice is D.

Question 2

If the objective lens of a compound microscope is replaced with a lens of double the focal length while the eyepiece also has its focal length halved, what will happen to the overall magnification of the microscope?

Accepted Answer

The overall magnification of a compound microscope is given by the product of the magnification of the objective lens and the magnification of the eyepiece. If the objective lens is replaced with a lens of double the focal length, its magnification will be halved. If the eyepiece also has its focal length halved, its magnification will be doubled. Therefore, the overall magnification of the microscope will remain the same.

Question 3

If a person is nearsighted the corrective lens will:

Accepted Answer

Nearsightedness means a person can see objects clearly only if they are close to the eyes. Corrective lenses for nearsightedness (myopia) are designed to take objects that are at infinity (very far away) and form an image at the person's far point, which is the farthest distance at which they can see clearly without correction.

Question 4

A magnifier uses a:

Accepted Answer

A magnifier uses a converging lens to form a virtual image that is larger than the object, allowing for magnification.

Question 5

A converging lens will be prescribed by the eye doctor to correct which of the following?

Accepted Answer

A converging lens is used to correct farsightedness because it helps focus light directly on the retina by converging light rays that would otherwise focus behind the retina.

Question 6

A lens with a focal length of 12 cm has what refractive power?

Accepted Answer

The answer of A lens with a focal length of...

Question 7

You are designing contact lenses for someone whose near point is 43 cm. What focal length lens should you prescribe so that an object can be clearly seen when placed at 25 cm in front of the eye?

Accepted Answer

The answer of You are designing contact lenses for someone...

Question 8

A compound microscope has an eyepiece that:

Accepted Answer

The eyepiece of a compound microscope uses the real image formed by the objective lens as the object and magnifies it to form a virtual image for the viewer.

Question 9

A magnifying lens of refractive power d (in diopters) gives what magnification when the viewing eye is relaxed assuming a near point of 25 cm?

Accepted Answer

The answer of A magnifying lens of refractive power d...

Question 10

What is the magnitude of the approximate magnification of a compound microscope with objective and eyepiece focal lengths of 0.90 cm and 3.6 cm, respectively, and a separation between lenses of 20 cm?

Accepted Answer

The answer of What is the magnitude of the approximate...

Question 11

A person can see well close up, but cannot do so in the distance. To correct this, lenses that are _____ having a _____ refractive power could be used.

Accepted Answer

The answer of A person can see well close up,...

Question 12

A nearsighted person cannot see objects clearly beyond 50 cm (the far point). If the patient has no astigmatism and contact lenses are prescribed, what is the power of the lens required to correct the patient's vision?

Accepted Answer

The power of the lens required to correct the patient's vision is given by the formula:P = 1/f = 1/(d_o - d_i)where d_o is the object distance (50 cm) and d_i is the image distance (at the retina, which is about 2.5 cm).Plugging in these values, we get:P = 1/f = 1/(0.5 m - 0.025 m) = 2.0 diopters

Question 13

A lens is used as a magnifier. Which of the following statements is incorrect?

Accepted Answer

A magnifying lens is typically a convex lens, which has a positive focal length, not negative.

Question 14

A given individual is unable to see objects clearly when they are beyond 75 cm. What focal length contact lens should be used to correct this problem?

Accepted Answer

The answer of A given individual is unable to see...

Question 15

While a camera has film where the image is formed, the eye forms the image on the:

Accepted Answer

The retina is the part of the eye where the image is formed, similar to how film is used in a camera to capture images.

Question 16

You are building a compound microscope with an objective lens of focal length 1.1 cm and an eyepiece lens of focal length 5.0 cm. You mount the lenses 18 cm apart. What is the approximate magnification of your microscope?

Accepted Answer

The magnification of a compound microscope is given by the formula:

m = (-) (f_obj / f_eye)

where f_obj is the focal length of the objective lens, and f_eye is the focal length of the eyepiece lens.

Substituting the given values, we get:

m = (-) (1.1 cm / 5.0 cm) = (-) 0.22

The negative sign indicates an inverted image, which is typical for compound microscopes. The absolute value of the magnification is:

|m| = 1 / (18 cm / 1.1 cm + 1)

|m| = 80.39

Rounding off to the nearest integer, we get a magnification of 80, which corresponds to answer choice C.

Question 17

A simple magnifier makes an image appear at the near point distance from the eye of the viewer (25 cm). What is the magnifying power of the magnifier if it is constructed of a lens of focal length of 6.3 cm? Do not use the approximation formula.

Accepted Answer

The answer of A simple magnifier makes an image appear...

Question 18

Which of the following would decrease the magnification of a compound microscope?

Accepted Answer

According to the formula for magnification of a compound microscope, M = Magnification of objective lens x Magnification of eyepiece lens. This means that if we replace the objective lens with one of longer focal length, the magnification of the objective lens will decrease, resulting in an overall decrease in the magnification of the microscope.

Question 19

Doubling the focal length of the objective lens of a compound microscope will change the magnification by what factor?

Accepted Answer

Doubling the focal length of the objective lens will halve the magnification, as magnification is inversely proportional to the focal length of the objective lens.

Question 20

A magnifying lens with a focal length of 10 cm has what maximum magnification? (Assume the near point is 25 cm). Do not use the approximation formula.

Accepted Answer

The answer of A magnifying lens with a focal length...

Quiz 26: Applications of Optics