Page 737 - SUBSEC October 2017_Neat

02238020/CAPE SPEC/MS/2017
7

Question 3 KC UK XS

(a) (i) A theory that seeks to explain the behaviour of light 2
as waves (1) and in some cases as particles (1).

(ii) λ = h 1
P

(b)
(i)

Φ = 2.2 eV

1 1
14
f0 = W (1) = 2.2 x 1.6 x 15 -19 = 5.37 x 10 Hz (1)
h 6.55 x 10 -34 Js

(ii)

KE max 1
E = hf + Φ
E = hc + Φ (1)


1
8
= 6.63 x 10 -34 x 3 x 10 + 2.2 x 10 -19
-7
4 x 10
(iii)
= 7.17 x 10 -19 J (1)

Stopping potential

eVs = hf – W 1
8
= 6.63 x 10 -34 x 3 x 0.10 – 2.2 x 10 -19
4 x 10
-7

eVs = 4.12 x 10 -15

Vs = 4. 12 x 10 -15 (1)
1.6 x 10 -19