A slit of width 'd' is illuminated by light of wavelength 6000 A. For what value of d will i) the first maximum fall at an angle of 30°. ii) First minimum fall at an angle of 30°.

Q. A slit of width

a

is illuminated by parallel monochromatic light of wavelength

λ .

The value of

a

at which the first minimum of the diffraction pattern will from at

θ = 30^{\circ}

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A slit of width a is illuminated by the red light of wavelength 6500A0. If the first minimum falls at θ = 30o, the value of a is

The correct option is B 1.3micronAccording to principle of diffraction, a sinθ=nλ where,n= order of secondary minimumor, asin30o=1×(6500×10−10)or, a=1.3×10−6 m, or , a=1.3micron.

A slit of width a is illuminated by the red light of wavelength $6500 A^{0}$ . If the first minimum falls at $θ$ = 30 $^{o}$ , the value of a is

The correct option is B $1.3 m i c r o n$
According to principle of diffraction, a $s i n θ = n λ$
where, $n =$ order of secondary minimum
or, $a s i n 30^{o} = 1 \times (6500 \times 10^{- 10})$
or, $a = 1.3 \times 10^{- 6}$ m,
or , $a = 1.3 m i c r o n .$