Check Test 1 - Optics
1 Which device necessarily forms a virtual image of a real object?
a A convex lens.
A convex mirror.
2 Which rays (marked A, B, C and D) are the usual choices when completing the ray diagram for a microscope.
3 Which statement is incorrect .....
A prediction made with a standard ray diagram is more accurate than an prediction based on the thin lens formula.
4 A student sees two images of a ceiling light when he looks for the reflections in a lens. Which of the following completed statements is incorrect?
An image which is above the lens can always be......
... shown to be formed by the top surface of the lens.
5 A partial ray diagram is shown for a magnifying glass.
Which statement is correct?
The object is at C and the image is at A.
6 Following the normal sign convention, the focal lengths of which two devices are both positive?
A concave mirror and a convex lens.
7 The image of a real object formed by a single convex mirror is always ....
... upright.
8 Which of the following telescopes has a concave eyepiece?
Galilean.
9 A simple two lens refracting telescope is four meters long. The focal length of the eyepiece is 2 cm.
The magnification of the telescope is approximately ....
... x 200
10 Which of the following statements is incorrect?
The advantages of a Newtonian telescope over the earlier refracting instruments included the following ...
Only one large curved (spherical) surface needed to be made.
11 You have several lenses as shown.
Which would be the best selection with which to make a simple microscope.
.... A as objective and D as eyepiece.
12 A simple microscope is made from two lenses. The best place for the object is at ........
13 The final image in a microscope is often formed at infinity because......
.... The eye is relaxed when viewing images at infinity.
14 A microscope has an objective with a magnification of x10, and an eyepiece with a magnification of x 2.
The magnification of the microscope is ..
.... x 20
15 The operating principle of the optical fiber is best described as ...
..... total internal reflection.
16 The plastic sheath on the outside of a glass optical fiber is put there to ....
..... to prevent signals leaking between fibers.
17 Infrared light is chosen for signal transmission on optical fibers because ....
.... glass is transparent in the infrared.
18 Colored fringes around bright objects seen in a microscope are due to ....
... chromatic aberration.
19 The main mirror of the Hubble Space telescope caused spherical aberration in the images.
The images were ......
..... blurred.
20 A student has made a microscope which has a blurred image surrounded by colored fringes.
To partially correct both effects he should.
..... use a lens stop.
21 Two lenses are selected with powers of +5 and -2.
The focal lengths of the lenses are ..... (respectively).
..... 20 cm and - 50 cm
22 The most intense wavelength of sunlight may be taken as .....
..... 500 nm.
23 A single slit is placed in a narrow beam of sunlight.
The width of the central maximum of the single slit interference pattern on a distant screen can be calculated by knowing ....
... the width of the slit, the wavelength of sunlight and the distance to the screen.
24 The images of two stars in a telescope are just resolved by Rayleigh's criterion.
The images can be described as two overlapping circular ripple patterns.
25 A student is not able to resolve two distant yellow car headlights at night.
Which of the following statements is incorrect.
He would be more likely to resolve the headlights if they were less bright.