AIIMS 2019 Physics Resonance MCQ Question

To find the value of $x$ using equations (I) and (II), we can express $l_1$ and $l_2$ in terms of $x$ and the wavelength $\lambda$. From equation (I), we have $l_1 = \frac{\lambda}{4} - x$, and from equation (II), $l_2 = \frac{3\lambda}{4} - x$. Substituting these into the expression for $x$ gives $x = l_2 - \frac{3}{2} l_1$, confirming option A.

Option B is incorrect as it does not derive from the equations provided. Option C may be a numerical solution but lacks context without specific values for $l_1$ and $l_2$. Option D does not follow from the equations given and does not relate to the calculations needed to find $x$.