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A slit of width a is illuminated by whit...

A slit of width a is illuminated by white light. For red light `(lambda=6500Å)`, the first minima is obtained at `theta=30^@`. Then the value of a will be

A

3250

B

`6.5 xx 10^(-4)mm`

C

`1.3 mu m`

D

`2.6 xx 10^(-4)cm`

Text Solution

Verified by Experts

The correct Answer is:
C
`a sin theta = n lambda`
`rArr a = (lambda)/(sin 30^(@))`
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Knowledge Check

  • A slit of width is illuminated by white light. For red light (lambda=6500Å) , the first minima is obtained at theta=30^@ . Then the value of will be

    A
    (a) `3250Å`
    B
    (b) `6.5xx10^-4mm`
    C
    (c) `1.24`
    D
    (d) `2.6xx10^-4mm`

  • A slit of width a illuminated by red light of wavelength 6500 Å . The first minimum will fall at theta=30^(@) if a is

    A
    `3250 Å`
    B
    `6.5xx10^(-4) mm`
    C
    `1.3 micron`
    D
    `2.6xx10^(-4) cm`

  • A slit of width a is illuminiated by white light. The first diffraction minimum for light of lamda=6500 Å is formed at theta=30^(@) , then the width (a) of the slit is

    A
    `6.5xx10^(-5)m`
    B
    `13xx10^(-6)m`
    C
    `1.3mum`
    D
    `2.6xx10^(-5)m`

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