In a diffraction pattern due to single slit of width '$$a$$', the first minimum is observed at an angle of $$30^{\circ}$$ when the light of wavelength $$5400 \mathop A\limits^o$$ is incident on the slit. The first secondary maximum is observed at an angle of $$\left(\sin 30^{\circ}=\frac{1}{2}\right)$$

In a single slit experiment, the width of the slit is doubled. Which one of the following statements is correct?

The rays of different colours fail to converge at a point after passing through a thick converging lens. This defect is called

Two coherent sources of wavelength '$$\lambda$$' produce steady interference pattern. The path difference corresponding to 10$$^{th}$$ order maximum will be