CAIE A-Level Physics AS 8.3.4 Ax D for Double Slit Interference Using Light Questions

Use λ = ax / D to calculate fringe spacing in double-slit interference with light.

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Use λ = ax / D to calculate fringe spacing in double-slit interference with light.

[Maximum number: 3]

A laser emitting light of a single wavelength is used to illuminate slits $\mathrm{S}_{1}$ and $\mathrm{S}_{2}$ , as shown in Fig. 6.1.

Fig. 6.1 (not to scale)

An interference pattern is observed on the screen A B. The separation of the slits is 0.48 mm . The slits are 2.4 m from AB . The distance on the screen across 16 fringes is 36 mm , as illustrated in Fig. 6.2.

Fig. 6.2

Calculate the wavelength of the light emitted by the laser.
wavelength = m

$x=\lambda D / a$ $\lambda=\left(36 \times 10^{-3} \times 0.48 \times 10^{-3}\right) /(16 \times 2.4)$ $=4.5 \times 10^{-7} \mathrm{~m}$

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CAIE A-Level Physics AS 8.3.4 Ax D for Double Slit Interference Using Light Questions question 1