Everything Science Grade 10

11.5 CHAPTER 11. ELECTROMAGNETIC RADIATION

Exercise 11 - 2

1. Indicate the penetrating ability of the different kinds of EM radiation and

relate it to energy of the radiation.

2. Describe the dangers of gamma rays, X-rays and the damaging effect of

ultra-violet radiation on skin.

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(1.) 004t (2.) 004u

Particle-like nature of

EM radiation

ESADM

When we talk of electromagnetic radiation as a particle, we refer to photons, which are

packets of energy. The energy of the photon is related to the wavelength of electromagnetic

radiation according to:

DEFINITION: Planck’s constant

Planck’s constant is a physical constant named after Max Planck.

h= 6, 63 × 10 −^34 J·s

The energy of a photon can be calculated using the formula:

E=hf

or

E=hcλ,

196 Physics: Waves, Sound and Light