Deck 5 = Physics Spring Term 2014

Question 1

What is wave speed measured in?

Answer 1

-(m/s)

Question 2

What is a wave?

Answer 2

-A wave is an oscillation along a medium.

Question 3

What is a medium?

Answer 3

-A medium is the things that vibrates.

Question 4

What are oscillation?

Answer 4

-Oscillations are another word for vibrations and convey the direction of energy transfer.

Question 5

What is the frequency of the waves?

Answer 5

This is the number of waves passing through a any point per second.

Question 6

What is the unit for frequency?

Answer 6

-Hz.

Question 7

What is the time for one oscillation called?

Answer 7

-It is called a period.

Question 8

What is the wave length?

Answer 8

-This is the distance between any point when the wave makes a full cycle, the line comes back to the same point.

Question 9

What is the amplitude of a wave?

Answer 9

-This is the maximum distance a point moves from its rest position when a wave passes.

Question 10

Examples of transverse waves?

Answer 10

-Light, surface water waves.

Question 11

Examples of longitudinal waves?

Answer 11

-Sound waves, pressure waves, ultrasound.

Question 12

What is wavelength measured in?

Answer 12

-(m).

Question 13

What is amplitude measured in?

Answer 13

-(m).

Question 14

What is the wave equation?

Answer 14

-speed = frequency x wavelength.

Question 15

What is the law of reflection?

Answer 15

• i=r.

- angle of incidence = the angle of reflection.

Question 16

Rules of electromagnetic waves?

Answer 16

-All are transverse, All travel at the speed of light in a vacuum

Question 17

Speed of light in a vacuum?

Answer 17

-300’000km per second.

Question 18

Define transverse wave?

Answer 18

-There oscillation are at right angles to the direction of travel. the waves transfer energy and a material gains energy when it absorbs them

Question 19

Where do electromagnetic waves come from?

Answer 19

-They are emitted whenever charged particles oscillate or lose energy in some way.

Question 20

What is the refractive index?

Answer 20

-In a vacuum, the speed of light is 300’000km/s, in air is nearly the same. However in glass it slows to 200’000km/s. refractive index = 300 000 / 200 000 = 1.5

Question 21

Refractive index of light in a vacuum?

Answer 21

-1

Question 22

What are the units of refractive index?

Answer 22

-None.

Question 23

Low refractive index to high

Answer 23

-Speed decreases, Direction bends towards the normal, frequency stays the same, Wavelength decreases.

Question 24

High refractive index to low

Answer 24

-Speed increases, direction bends towards the normal, frequency stays the same, wavelength increases.

Question 25

Angles of incidence and reflection always...

Answer 25

-Touch a normal.

Question 26

What is Snell's law?

Answer 26

-Snell's law can be used to calculate the refractive index of the glass block.

Question 27

Equation for Snell's law?

Answer 27

-N= sini/sinr n = refractive index.

Question 28

The bigger the refractive index..?

Answer 28

-The slower the light will travel through the material.

Question 29

Light entering semi-circular glass block?

Answer 29

-Diagrams show the same rules as normal refraction. Find the normal first. Light will bend towards the normal.

Question 30

What is total internal reflection?(TIR)

Answer 30

-This is when the angle of incidence is greater than the critical angle. Both angles become equal.

Question 31

What are uses of (TIR)?

Answer 31

-Cats eyes, light is reflected in prisms. Binoculars, lights is reflected in prisms like periscope. Windshield rain sensor, light beamed at the windscreen to see if there is rain drops, they will reflect if there are.

Question 32

Experiment to determine the refractive index of glass?

Answer 32

-Look in book, or on sheet for info.

Question 33

What is diffraction?

Answer 33

-Diffraction is when a wave bends around an obstacles to fill in the shadows behind it. Diffraction is only significant when wavelength is roughly the same as the obstacles size. (look at diagrams)

Question 34

Finding the speed of sound in air?

Answer 34

-Look in book.

Question 35

A use of ultrasound, range finding?

Answer 35

-Look in book.

Question 36

A straight line on a Hooke's law graph shows that?

Answer 36

Proportional Hooke's law is being obeyed

Question 37

Curved line on Hooke's law graph shows that?

Answer 37

in proportional Hooke's law disobeyed and the elastic band has been permanently streached