Optics Ques 197
- The phases of the light wave at $c, d, e$ and $f$ are $\phi _c, \phi _d, \phi _e$ and $\phi _f$ respectively. It is given that $\phi _c \neq \phi _f$
$(2007,4 M)$
(a) $\phi _c$ cannot be equal to $\phi _d$
(b) $\phi _d$ can be equal to $\phi _e$
(c) $\left(\phi _d-\phi _f\right)$ is equal to $\left(\phi _c-\phi _e\right)$
(d) $\left(\phi _d-\phi _c\right)$ is not equal to $\left(\phi _f-\phi _e\right)$
Show Answer
Answer:
Correct Answer: 197.(c)
Solution:
All points on a wavefront are in phase.
$\therefore \quad \phi _d =\phi _c \text { and } \phi _f=\phi _e $
$\therefore \quad \phi _d-\phi _f =\phi _c-\phi _e$
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