0
$\begingroup$

What happens to the intensity of an electromagnetic wave if the amplitude of the electric field is halved?

$\endgroup$
  • $\begingroup$ Intensity of an electromagnetic wave is directly proportional to the square of amplitude of the wave. $\endgroup$ – walber97 Mar 20 at 6:33
1
$\begingroup$

The intensity if an electromagnetic wave is the square of the amplitude $I=A^2$, which means that if $A_{new}=\frac{A}{2}$ the intensity becomes $I_{new}=\left(\frac{A}{2}\right)^2=\frac{A^2}{4}$ and we can see that the intensity is one quarter of what it was before.

$$ \frac{I_{new}}{I}=\frac{\left(\frac{A^2}{4}\right)}{A^2}=\frac{1}{4}$$ which gives us $$I_{new}=\frac{I}{4}$$

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.