Question 209: EM waves

Question

The electric field associated with an em wave in vacuum is given by 
E = $$\widehat i$$ 40 cos (kz $$-$$ 6 $$ 	imes $$ 108 t) where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is

Accepted Answer

Compare the given equation with
E = E
0
cos(kz - $$\omega t$$)
we get, $$\omega $$ = 6 $$ 	imes $$ 10
8
s
-1
Wave vector, k = $${\omega  \over c}$$ = $${{6 	imes {{10}^8}} \over {3 	imes {{10}^8}}}$$ = 2 m
-1

Answer

2 m$$-$$1

Answer

0.5 m$$-$$1

Answer

6 m$$-$$1

Answer

3 m$$-$$1

EM waves

The electric field associated with an em wave in vacuum is given by E = $\widehat i 40 cos (kz - 6 \times $ 108 t) where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is

Choose the correct answer: