Wave

Question 1

Definition of Waves?

• p___ o___ (meaning of each word) of _____ repeating regularly in s___ and t____

Answer 1

• PERIODIC OSCILLATION (occurring @ intervals; back and forth movement) of ENERGY repeating regularly in SPACE and TIME

Question 2

PROPERTIES OF WAVES (definition + unit)
1. W___
2. F____
3. A____ (2)
4. S____

Answer 2

1. Wavelength (distance between two crests/troughs/ ; meters)
2. Frequency (# of oscillations per given time but usually per second / Hertz)
3. Amplitude (half the peak-to-trough height ; directly proportional to energy)
4. Speed (frequency x wavelength ; m/s)

Question 3

ELECTROMAGNETIC Waves DEFINITION

• periodic oscillation of ____ and ____ fields which are p_____ to each other

Answer 3

• periodic oscillation of electric and magnetic fields which are perpendicular to each other

Question 4

Behaviour of EM waves in a VACCUUM (specific value)

Answer 4

• all forms travel constantly @ 2.998 x 10^8 m/s (speed of light)

Question 5

MNEMONIC of EM waves + wavelength & frequency + wavelength / frequency of VISIBLE LIGHT and specific color

Answer 5

• Rich Men In Vegas Use Xpensive Gadgets
• VIOLET : 400 nm ; 7.5 x 10^14 Hz
• RED : 700 nm ; 4.3 x 10^14 Hz

Question 6

MAXWELL THEORY (other term + definition)

Answer 6

ELECTROMAGNETIC THEORY by james maxwell: light is a propagating wave of electric and magnetic field

Question 7

The Universe contains m____ (which has 3 pts) and e____ r_____ (which has NO 2 pts)

and such… were considered as two d___ and u____ phenomena

Answer 7

1. MATTER (mass, location, motion)
2. ELECTROMAGNETIC RADIATION (mass, location)
3. Distinct
4. Phenomena

Question 8

BLACKBODY RADIATION phenomena
1. definition
2. color of low/high temperature
3. definition of ___________
4. How it contradict classic physics?

KEYWORDS:
- UV catastrophe

Answer 8

1. EMR whose WAVELENGTH and COLOUR depend on object’s temperature
2. LOW = red ; HIGH = yellow/white
3. INTENSITY RADIATION: measure of energy emitted / unit area
4. Classic Physics : radiation intensity depicts a continuous SMOOTH curve to INFINITY as wavelength decreases

However….

in BR Phenomena, there’s a SHARP decrease in radiation intensity @ shorter wavelengths in the UV region — called UV catastrophe

due to EMR being QUANTIZED (according to MAX PLANCK)

Question 9

SIGNIFICANT FIGURES RULES (4 main)

33.2
92.00
5.02 x 10^4
0.0032
0.000500
5
405
320.

Answer 9

1. non zeroes
2. zeroes between 2 non zeroes
3. zeroes to the right of decimal pt and whole #
4. zeroes to right of a whole # w/ a decimal pt @ the end

3
4
3
2
3
1
3
3

Question 10

According to QUANTUM THEORY, r____ e___ is emitted by _____ or photons which serves as the smallest/biggest quantity of e_____ (atoms or molecules) that can be emitted or absorbed in the form of _____

Answer 10

• RADIANT ENERGY
• QUANTA
• ENERGY
• ELECTROMAGNETIC RADIATION

Question 11

Describe the relationship between the following:
1. frequency
2. wavelength
3. temperature
4. energy
5. intensity of radiation

Answer 11

wavelength is INVERSELY PROPORTIONAL to the rest

Question 12

QUANTUM THEORY

Which is more probable to lose/emit energy/intensity of radiation? Why? And where are each located in the EM spectrum?

low vs high energy quanta

Answer 12

low energy quanta

Question 13

PHOTOELECTRIC THEORY

What is the behaviour of the electrons when the light frequency that hit the metal surface is:

1. Below threshold
2. Above threshold

And what are the 2 relationships present when electrons are emitted?

How does this contradict classical physics

Answer 13

1. NO electrons are emitted
2. Part of the photons’ energy that strikes the metal detaches the electrons from the metal surface, while the remaining energy transforms to KET of the ejected electrons

DIRECTLY PROPORTIONAL
1. # of emitted electrons = light intensity (# of e- per sq cm)
2. kinetic energy = frequency

classical physics = electrons ejected is based on light intensity
BUT…. acc to Photoelectric theory, it’s based on frequency

Question 14

2 formulas required in speed of light and energy of photon + value of constants

Answer 14

speed of light = frequency x wavelength (m)
photon energy (J) = planck’s constant x frequency

light = 2.998 x 10^8
constant = 6.626 x10^-34