An electromagnetic wave has the following electric field 𝐸ሬԦ(𝑥, 𝑦, 𝑧) = 200 ( 𝑁
Posted: Wed May 04, 2022 1:19 pm
An electromagnetic wave has the following electric field 𝐸ሬԦ(𝑥,
𝑦, 𝑧) = 200 ( 𝑁 𝐶 ) cos(400𝜋 𝑡 − 𝑘(𝑦 + 𝑧)) 𝒊̂ Where (x, y, z) are
given in meters and t is given in seconds. If the speed of light is
𝑐 = 3 108𝑚/𝑠 , answer the following questions about this
electromagnetic wave. (a) (3 Pts.) What is the correct SI units for
𝑘? (b) (3 Pts.) What is the numerical value of 𝑘 (use 𝜋 = 3)? (c)
(3 Pts.) What is the frequency of this wave? (d) (3 Pts.) In which
direction is this electromagnetic wave propagating? (Give a vector
as your answer). (e) (3 Pts.) What is the wavelength of this wave?
(f) (3 Pts.) In which direction is the magnetic field of this wave
at the point 𝑥 = 0, 𝑦 = 0, 𝑧 = 0 at time 𝑡 = 0? The Poynting vector
of an electromagnetic wave is defined as 𝑆Ԧ = 1 𝜇0 𝐸ሬԦ × 𝐵ሬԦ (g) (3
Pts.) What is the direction of the Poynting vector for this
wave?
𝑦, 𝑧) = 200 ( 𝑁 𝐶 ) cos(400𝜋 𝑡 − 𝑘(𝑦 + 𝑧)) 𝒊̂ Where (x, y, z) are
given in meters and t is given in seconds. If the speed of light is
𝑐 = 3 108𝑚/𝑠 , answer the following questions about this
electromagnetic wave. (a) (3 Pts.) What is the correct SI units for
𝑘? (b) (3 Pts.) What is the numerical value of 𝑘 (use 𝜋 = 3)? (c)
(3 Pts.) What is the frequency of this wave? (d) (3 Pts.) In which
direction is this electromagnetic wave propagating? (Give a vector
as your answer). (e) (3 Pts.) What is the wavelength of this wave?
(f) (3 Pts.) In which direction is the magnetic field of this wave
at the point 𝑥 = 0, 𝑦 = 0, 𝑧 = 0 at time 𝑡 = 0? The Poynting vector
of an electromagnetic wave is defined as 𝑆Ԧ = 1 𝜇0 𝐸ሬԦ × 𝐵ሬԦ (g) (3
Pts.) What is the direction of the Poynting vector for this
wave?