Physics · Practical apparatus

Slit diffraction screen probe

Sweep the intensity probe and find the first minima on either side. Their separation measures central-maximum width. Repeat after changing slit opening while keeping wavelength and distance fixed.

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Slit diffraction screen probe

ஒளிச்செறிவு சோதனையை நகர்த்தி இருபுற முதல் குறைந்தபட்ச இடங்களைத் தேடவும். அவற்றின் இடைவெளி மைய அகலமாகும்.

Key notes, relationships and model limits

Key relationship

First minima y≈±λD/a; central width≈2λD/a.

Practical tip

Sweep the intensity probe and find the first minima on either side. Their separation measures central-maximum width. Repeat after changing slit opening while keeping wavelength and distance fixed.

Common trap

Central peak intensity does not by itself determine slit width.

Model limits

Fraunhofer coherent uniform slit; ideal intensity probe; width reading rounded to0.1 mm. No laser operation outside this virtual view is implied.

What you will learn

Measure a diffraction width with a virtual screen probe.

Try the experiment

Try both scenarios, change one control, and predict the result before checking the graph and readouts.

Think of it this way

Change one input while keeping the others fixed, as you would in a controlled experiment.

Worked example

600 nm,a0.2 mm,D1 m gives minima±3 mm and width6 mm.

Why this matters

The model connects slit diffraction screen probe with an observable reading. Check the equation and assumptions before applying it.

Before you start

SI units · algebra · graph reading

Check your understanding

The central width is found between?

Two adjacent maxima
The first minima on either side
The outer screen edges

Read the explanation

The central maximum ends at those first zeros.

Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.