Q149 · Practice questionSimple familiar1 mark
QUESTION 149
An electric charge oscillates and produces an electromagnetic wave in vacuum. Which statement correctly describes the wave?
(A)
It requires a material medium to propagate
(B)
Its electric and magnetic fields oscillate parallel to each other
(C)
Its electric and magnetic fields are perpendicular to each other and to the direction of propagation
(D)
Its electric field is parallel to the direction of propagation
WORKED SOLUTION
1 markAnswer C
ANSWER
C. Its electric and magnetic fields are perpendicular to each other and to the direction of propagation
Worked solution
An accelerating, oscillating charge produces changing electric and magnetic fields. In the transverse wave these fields are mutually perpendicular and perpendicular to propagation; a material medium is unnecessary.
Equivalent physically justified methods and consistent equivalent units accepted.
Displayed decimals are model answers; accept appropriate significant figures and consistent rounding from stated constants.
Select C.
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