Topic 8 Waves and Particle Nature of Light

Question 1

Explain ground state [1]

Answer 1

[1] Correct reference to stability/lowest energy state/level of the electron/ atom

Question 2

Explain what is meant by each of the terms in hf = k.e.max + φ [3]

Answer 2

[1] hf Energy of a photon
[1] k.e.max Kinetic energy of emitted electron/equivalent
[1] φ Energy to release electron from surface / equivalent

Question 3

Why are electrons of this wavelength useful for studying the structure of molecules? [2]

Answer 3

[1] λ

Question 4

What does the gradient on an energy frequency graph represent? [1]

Answer 4

[1] planks constant

Question 5

What does the y-intercept represent on an Energy-Frequency graph represent? [1]

Answer 5

[1] Work Function

Question 6

How can you make a linear graph out of hf = T + φ ? [3]

Answer 6

[1] T=hf–φ issimilartoy=mx+c
[1] Straight line shows T/f relationship
[1] Negative intercept T axis shows φ

Question 7

Explain what is meant by the term vertically polarised light (3)

Answer 7

(1) Unpolarised light has oscillations in all planes
(1) Vertically polarised light has oscillations only in the vertical plane
(1) The vertical plane includes direction of propagation of the light

Question 8

Explain results of electrons being fired through crystalline structure onto a fluorescent screen (3)

Answer 8

(1) electrons form diffraction patters
(1) behave like waves
(1) because diffraction patterns are wave properties