2. A photon of wavelength for 4 x10 -7 m strikes on the metal surface the work function of the metal being 2.13 eV. Calculate (i)the energy of the photon in
eV(ii) the kinetic energy of the emission(iii) velocity of the photoelectron
[1ev=1.602x10-19 J]

See explanation

Explanation:

Energy of the photon;

E = hc/λ

h= Planks constant

c= speed of light

λ = wavelength

E= 6.6 × 10^-34 × 3 × 10^8/4 x10 -7

E = 4.95 × 10^-19 J

If 1ev=1.602x10-19 J

x = 4.95 × 10^-19 J

x= 3.1 ev

From Einstein's photoelectric equation;

KE = E - Wo

Where;

KE = kinetic energy of ejected photoelectron

E= energy of the photon

Wo= work function of the metal

KE = 3.1 eV - 2.13 eV

KE= 0.97 eV

KE = 0.97 eV × 1.602x10-19 J

KE = 1.55 × 10^-19 J

KE = 1/2 mv^2

1.55 × 10^-19= 1/2 × 9.1 × 10^-31 × v^2

v= √2 × 1.55 × 10^-19/9.1 × 10^-31

v= 5.8 × 10^5 m/s

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).