Wave Optics - Result Question 4
4. Ratio of intensities of two waves are given by $4: 1$. Then the ratio of the amplitudes of the two waves is
[1991]
(a) $2: 1$
(b) $1: 2$
(c) $4: 1$
(d) $1: 4$
[1989]
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Answer:
Correct Answer: 4. (a)
Solution:
(a) $\frac{I_1}{I_2}=\frac{a_1^{2}}{a_2^{2}}=\frac{4}{1} \quad \therefore \frac{a_1}{a_2}=\frac{2}{1}$
If $w_1$ and $w_2$ are widths of two slits from which intensities of light $I_1$ and $I_2$ emanate, then $\frac{I_1}{I_2}=\frac{a^{2}}{b^{2}}=\frac{w_1}{w_2} ; a$ and $b$ are amplitudes.
