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## QuestionPhysicsClass 12

The wave function (in SI units) for an electromagnetic wave is given as
$$\psi (x,t)={ 10 }^{ 3 }\sin p{ \left( 3\times { 10 }^{ 6 }x-9\times { 10 }^{ 14 }t \right) }$$.The speed of the wave is:

(A) $$9\times { 10 }^{ 14 }$$
(B) $$3\times { 10 }^{ 8 }$$
(C) $$3\times { 10 }^{ 6 }$$
(D) $$3\times { 10 }^{ 7 }$$

The speed of the wave is given as $$v=\dfrac{\omega }{k}=\dfrac{9\times 10^{14}}{3\times 10^6}=3\times 10^8$$