unit 1a: electromagnetic radiation

Question 1

electromagnetic radiation

Answer 1

energy which travels from the sun to the earth as waves

Question 2

electromagnetic spectrum

Answer 2

radio - microwaves - infrared - visible - ultraviolet - xray - gamma

Question 3

energy and frequency along the spectrum

Answer 3

increases from radio to gamma

Question 4

wavelength along the spectrum

Answer 4

decreases from radio to gamma

Question 5

visible regions span

Answer 5

approximately 700nm to 400nm

Question 6

wavelength symbol, units, description

Answer 6

lambda , m or nm , distance between adjacent crests of a wave

Question 7

velocity symbol, units, description (speed of light)

Answer 7

c , m/s , rate of change of displacement of an object

Question 8

frequency symbol, units, description

Answer 8

f , Hz, number of wavelengths that pass a fixed point in one unit of time

Question 9

wavenumber symbol, units, description

Answer 9

v , 1/cm or 1/m , specified distance (1/lambda)

Question 10

converting m to nm

Answer 10

multiply by 1x10^9

Question 11

describing electromagnetic radiation

Answer 11

a wave and a particle (dual nature)

Question 12

electromagnetic radiations stream of particles

Answer 12

photons

Question 13

a photon carries

Answer 13

quantised energy, proportional to the frequency of radiation

Question 14

the energy carried by one photon is given by

Answer 14

E=hf or E=hc/lambda

Question 15

planck’s constant

Answer 15

h = 6.63x10^-34J

Question 16

the energy carried by one mole of photons is given by

Answer 16

E=Lhf or E=Lhc/lambda

Question 17

avogadros constant

Answer 17

L = 6.02x10^23 /mol

Question 18

how are lines produced on emission spectroscopy

Answer 18

an electron is excited and moves to a higher energy level, when it falls back to ground state, energy is emitted

Question 19

why are there multiple lines on spectroscopy

Answer 19

many different electron transitions