In Young’s double-slit experiment, the angular width of a fringe formed on a distant screen is 1°. The wavelength of light used is 6000 Å. What is the spacing between the slits?

• (A) 344mm
• (B) 0.1344mm
• (C) 0.0344mm
• (D) 0.034mm

To find the spacing between the slits in Young's double-slit experiment, we can use the formula for angular fringe width:

Formula for Angular Fringe Width

The angular width of the fringe is given by:

θ = λ / d

Where:

• θ = angular width in radians
• λ = wavelength of light
• d = spacing between the slits

Convert Angular Width

First, we need to convert the angular width from degrees to radians:

θ = 1° = (1 × π) / 180 ≈ 0.01745 radians

Wavelength Conversion

The wavelength given is 6000 Å, which can be converted to meters:

λ = 6000 Å = 6000 × 10^-10 m = 6 × 10^-7 m

Calculate Slit Spacing

Now, rearranging the formula to find d gives us:

d = λ / θ

Substituting the values:

d = (6 × 10^-7 m) / 0.01745 ≈ 0.0344 mm

Final Answer

The spacing between the slits is 0.0344 mm, which corresponds to option (C).