Unit C: Electromagnetic Radiation

Question 1

Is a concave lenses focal length positive or negative?

Answer 1

Negative

Question 2

Is a concave mirrors focal length positive or negative?

Answer 2

Positive

Question 3

Is a convex lenses focal length positive or negative?

Answer 3

Positive

Question 4

Is a convex mirrors focal point positive or negative?

Answer 4

Negative

Question 5

What is the order of the electromagnetic spectrum, largest wavelength to shortest?

Answer 5

Radio->Micro->Infrared->Visible->UV->Xray->Gamma

Question 6

What wavelength range, in nanometers, does visible light occur?

Answer 6

400nm(purple) to 700nm(red)

Question 7

Distances that are virtual (objects, images, or focal lengths) are positive or negative numbers?

Answer 7

Negative numbers

Question 8

Erect images and objects have a ________ height.

Answer 8

Positive

Question 9

________ images have a negative height.

Answer 9

Inverted

Question 10

________ magnification means the image is erect, while _______ magnification means the image is _______.

Answer 10

Positive, negative, inverted.

Question 11

A wave has a speed of 5.0 x 10^-1 m/s and a wavelength of 2.0m. What is it’s period?

Answer 11

4 seconds

Question 12

At what speed does all EMR travel at?

Answer 12

3.00 x 10⁸ m/s (The speed of light)

Question 13

A water wave has a wavelength of 5.0m and a speed of 2.5 m/s. What is the period of this wave?

Answer 13

2 seconds

Question 14

A radio station broadcasts at a frequency of 1.00 x 10⁶ Hz. If the speed of this wave is 3.00 x 10⁸ m/s, what is it’s wavelength?

Answer 14

300m

Question 15

While floating on your air mattress on a river, you bob up and down 40 times in 5.0 min and you estimate the distance between the crests is 4.0m. What is the estimated speed of the waves?

Answer 15

5.3 x 10^-1 m/s

Question 16

The Law of Reflection states the angle of ________ equals the angle of reflection.

Answer 16

Incidence

Question 17

Size of image compared to size of object:

Answer 17

Magnification

Question 18

A beam of light travelling in glycerin hits the boundary between itself and water at an angle of 43° from the normal. Determine the angle of refraction through the water.

Refracive index of water: 1.33
Refractive index of glycerin: 1.47

Answer 18

49 degrees

Question 19

What is the critical angle between an air
(n=1.00)-water (n= 1.33) interface?
Note: We must go from more dense to less
dense.

Answer 19

49 degrees

Question 20

r/2, or half the radius of the curvature, equals the:

Answer 20

Focal Length (f)

Question 21

A diverging mirror has a radius of 20cm. An object is placed 30 cm in front of the mirror. Determine where the image will appear.

Answer 21

7.5 cm behind the mirror

Question 22

Converging lenses are ______ in shape,
Diverging lenses are _______ in shape.

Answer 22

Convex, concave

Question 23

A converging lens has a focal length of 0.22 m. If an object is placed 0.41 m in front of the lens, determine where the image will appear and identify its characteristics.

Answer 23

Real, inverted, larger

Question 24

In a wave:
Where crest meets crest, there is ___________ interference and a bright spot appears.
Where crest meets trough, there is ___________ interference and a black spot appears.

Answer 24

Constructive, destructive

Question 25

A pair of screens are placed 13.7m apart. A third order fringe is seen on the screen 2.50cm from the central fringe. If the slits were cut 0.0960 cm apart, determine the wavelength and colour of this light.

Answer 25

Question 26

If a yellow light with a wavelength of 540 nm shines on a double slit with the slits cut 0.0100mm apart, determine what angle you should look away from the central fringe to see the second order fringe.

Answer 26

Question 27

List the seven colours of the visible light spectrum from high energy to low energy.

Answer 27

Violet, indigo, blue, green, yellow, orange, red.

Question 28

Calculate the period of the wave for a blue laser diode having a frequency of 4.23 x 10¹⁴ Hz.

Answer 28

Question 29

Electromagnetic radiation, listed in order of increasing energy, is: a. radio wave, X ray, microwave, infared b. AC, radio wave, visible, infared c. microwave, visible, infared, UV d. microwave, infared, visible, X ray

Answer 29

d. microwave, infared, visible, X ray

Question 30

A pen laser has a wavelength of 460nm. The location in the spectrum of the laser beam produced by this pen laser is most likely: a. Red b. Orange c. Blue d. UV

Answer 30

c. Blue

Question 31

Determine the time required for a radio signal to reach Earth if it was sent from Mars from a distance of 7.80 x 10¹⁰ m when it is closest to the Earth.

Answer 31

t=d/v 260 seconds

Question 32

Electromagnetic radiation that has a wavelength of 260 m is classified as: a. Infrered b. Gamma c. Visible d. Radio

Answer 32

d. Radio

Question 33

What is the index of refraction?

Answer 33

The ratio of the speed of light in a vacuum and the speed of light in a specific medium/substance. n=c/v

Question 34

In a medium where the speed of light is 2.00 x 10⁸ m/s the index of refraction is:

Answer 34

n=c/v n=1.50

Question 35

A critical angle may be calculated only if: a. the light is passing from a high to a low speed medium b.the light is passing from a low to a high speed medium c. the incident ray is not reflected d. the resulting angle of refraction is known

Answer 35

b.the light is passing from a low to a high speed medium

Question 36

A ray of light from air strikes the surface of a block of glass, having a refractive index of 1.50, at an angle of 67 degrees. Determine the angle of refraction.

Answer 36

38 degrees

Question 37

Lucite is a strong clear plastic used for many windows. Determine the critical angle for a water Lucite system. The refractive index of water is 1.33 and 1.51 for Lucite.

Answer 37

61.7 degrees

Question 38

A Michelson type experiment was done to measure the speed of light in a substance. The eight sided mirror and the reflecting mirror were placed at opposite ends of an 18.0 km pipe of beer. The minimum frequency of rotation required to make a successful reading was found to be 990 Hz. What is the speed of light in the substance?

Answer 38

Question 39

A 3.0 cam tall object is placed 15 cam in front of a concave (converging) mirror which has a radius of 20 cm. What is the image distance? What is the size of the image? Describe the image characteristics.

Answer 39

Question 40

An 8.0 cm high object is placed 18 cm from a convex (diverging) mirror having a focal length of 10 cm. Where is the image? What is the size of the image? Describe the image characteristics.

Answer 40

Question 41

An object 3.0 cm high is 15 cm from a convex (converging) lens of 6.0 cm focal length. What is the distance to the image and the height of the image? Describe the image characteristics.

Answer 41