G10 Optical Instruments

Question 1

is a hand-held tool used to view smaller objects

one of the simplest optical instruments and is comprised of just a single converging lens

Answer 1

magnifying glass

Question 2

As the object moves _ to the eye, the angle increases and as a result, a _ image is observed.

Answer 2

closer, larger

Question 3

However, the eye cannot focus on an object closer than 25 cm. This is referred to as the

Answer 3

near point

Question 4

However, the eye cannot focus on an object closer than 25 cm. This is referred to as the

Answer 4

near point

Question 5

To increase the apparent size of the object being observed, a _ _ can be placed in front of the eye while the object is positioned at the focal length of the lens.

Answer 5

converging lens

Question 6

In this setup, the virtual image is at _, making the muscle of the eye more relaxed and the image more comfortable to view.

Answer 6

infinity

Question 7

The image formed by the magnifying glass is always _, _, and _

Answer 7

virtual, upright in position, and enlarged.

Question 8

angular magnification

efficiency of a magnifier

Answer 8

given by the ratio of the angle with the magnifier (θ) to the angle without the magnifier (θ0)

Question 9

If the object is at the near point of the eye, the maximum angular magnification is given by this equation

Answer 9

m(max)=1+25cm/f

Question 10

regular angular magnification

Answer 10

m=θ/θ(0)

angle with the magnifier (θ) to the angle without the magnifier (θ0).

Question 11

The object must be placed at the focal point of the lens for the image to be at infinity. This relationship is expressed by the equation

Answer 11

m=θ/θ0=25cm/f

Question 12

angle with a magnifier

Answer 12

θ

Question 13

angle without a magnifier

Answer 13

θ0

Question 14

focal length

Answer 14

f

Question 15

Higher magnification that cannot be provided by a simple magnifier can be achieved by using a combination of two lenses in a device

Answer 15

microscope, sometimes compound microscope

Question 16

used to focus the object under the microscope with wide range of magnifications and a very short focal length which is usually less than one centimeter

Answer 16

objective lens

Question 17

used to observe the object or specimen being studied. It usually has a magnification of 10 to 15 times and a focal length of a few centimeters

Answer 17

ocular lens

Question 18

ocular lens is also called

Answer 18

eyepiece

Question 19

The image formed by the _ lens, becomes the object for the _ lens.

Answer 19

objective, ocular

Question 20

The object is placed outside the focal length of the objective which forms a _, _ and _ image that is at or inside the focus of the eyepiece

Answer 20

real, inverted and enlarged

Question 21

The eyepiece which acts as a simple magnifier uses the image produced by the objective lens as its ‘_’.

Answer 21

object

Question 22

The eyepiece which acts as a simple magnifier uses the image produced by the objective lens as its ‘object’. As a result, it produces a second image which is considered as the “_”.

Answer 22

final image

Question 23

This second image that we observe is _, _, and _ compared to the original object.

Answer 23

virtual, inverted and very much enlarged

Question 24

The angular magnification between the angular sizes of the virtual image as seen through the eyepiece and of the real image if viewed without the eyepiece is expressed by the equation below:

Answer 24

m=M(1)m(e)=[-L/f(o)][25cm/f(e)]

Question 25

overall magnification of the compound microscope

Answer 25

m

Question 26

lateral magnification of the objective lens

Answer 26

M(1)

Question 27

angular magnification of the eyepiece

Answer 27

m(e)

Question 28

distance between the objective lens and eyepiece

Answer 28

L

Question 29

focal length of the objective lens

Answer 29

f(o)

Question 30

focal length of the eyepiece

Answer 30

f(e)

Question 31

optical system that is used to view distant objects. This is used to view large objects at huge distances while microscopes are used to view small objects close at hand

Answer 31

telescope

Question 32

uses a combination of two lenses to form an image

Answer 32

refracting telescope

Question 33

The objective lens forms a _ and _ image of a distant object either near or exactly at the focal point of the eyepiece.

Answer 33

real and inverted

Question 34

The second image or the final image seen in the eyepiece is an _, _ and _ image of the actual object.

Answer 34

enlarged, virtual, and inverted

Question 35

are useful in viewing relatively nearer objects, such as the sun, the moon or the planets

Answer 35

Refracting telescopes

Question 36

Very distant objects, such as stars will always appear as _ _ _ _no matter how angular magnification is increased

Answer 36

miniscule points of light

Question 37

angular magnification of a refracting telescope is given by

Answer 37

m=θ/θ(o)=f(o)/f(e)

Question 38

angle subtended by the object at the objective lens

Answer 38

θ(o)

Question 39

angle subtended by the final image at the eyepiece lens

Answer 39

θ

Question 40

focal length of the objective lens

Answer 40

f(o)

Question 41

focal length of the eyepiece lens

Answer 41

f(e)

Question 42

uses a combination of a curved mirror and a lens to form an image type of telescope is commonly used when viewing very far objects such as stars

Answer 42

reflecting telescope

Question 43

simply a pair of small telescopes attached side by side. It is used to view images of greater depth

Answer 43

Binoculars

Question 44

image formed using binoculars

Answer 44

upright

Question 45

an optical device used for recording images either electronically or on film

Answer 45

camera

Question 46

working principle is similar in many ways on the structure and function of the _ _ (camera)

Answer 46

human eye

Question 47

has a _ which works similarly to the eyelid of the human eye. allows the light to enter when opened and blocks the light when closed

Answer 47

shutter

Question 48

The hole behind the camera is called _, similar to the eye’s pupil. It serves as the pathway of light to the camera

Answer 48

aperture

Question 49

Another part of a camera is the _. It functions similarly to the iris. It regulates the amount of light entering the aperture which affects the lighting in a photograph.

Answer 49

diaphragm

Question 50

camera has used this to focus the light to produce bright and clear images

Answer 50

converging lens

Question 51

Lastly, a camera has a converging lens used to focus the light to produce bright and clear images. The lens forms an _, _ image on the recording medium.

Answer 51

inverted, real

Question 52

The recording medium is similar to the eye’s

Answer 52

retina.

Question 53

Diaphragm functions similarly to the _.

Answer 53

iris

Question 54

Aperture is similar to the eye's _

Answer 54

pupil

Question 55

shutter which works similarly to the _

Answer 55

eyelid

Question 56

When a camera is in focus, the position of the recording medium is at the _ position as that of the image formed by the lens.

Answer 56

same

Question 57

When a camera is in focus, the position of the recording medium is at the same position as that of the image formed by the lens. This results in a _ image.

Answer 57

sharp

Question 58

Remember that in a converging lens, the image distance _ as the object distance _.

Answer 58

increases, decreases

Question 59

Generally speaking, capturing an image of a distant object requires a lens of longer focal length. This is commonly called as _.

Answer 59

zoom lens

Question 60

A lens of shorter focal length produces a smaller image but larger field of view. This is commonly known as “_ _ lenses” or ‘_’ lenses.

Answer 60

wide angle, fisheye

Question 61

The amount of light entering the lens is controlled by the _ _ and its _ _.

Answer 61

camera’s shutter and lens aperture

Question 62

The _ regulates the time interval by which light is allowed to enter the lens

Answer 62

shutter

Question 63

This factor can be adjusted in a camera to factors of about 2, usually from _ to _.

Answer 63

1s to 1/1000 s

Question 64

Photographers refer to this light-gathering capability as the f-number of the lens which is mathematically expressed as

Answer 64

f-number=f/d

Question 65

focal length

Answer 65

f

Question 66

D

Answer 66

aperture diameter

Question 67

The _ _ _ increases with the f-number

Answer 67

depth of field

Question 68

forms an image with objects at one distance in focus and the rest of the image out of focus

Answer 68

low f-number

Question 69

forms a sharp image of an object at very far distances

Answer 69

high f-number