Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : In Young's double slit experiment, the fringes produced by red light are closer as compared to those produced by blue light. Reason (R): The fringe width is directly proportional to the wavelength of light. In the light of the above statements, choose the correct answer from the options given below :

Assertion (A): In Young's double slit experiment, fringes produced by red light are closer compared to those produced by blue light.

Reason (R): The fringe width is directly proportional to the wavelength of light.

In Young's double slit experiment, the fringe width is given by $$\beta = \frac{\lambda D}{d}$$ where $$\lambda$$ is the wavelength, $$D$$ is the screen distance, and $$d$$ is the slit separation. From the formula, $$\beta \propto \lambda$$, showing that the fringe width is indeed directly proportional to the wavelength of light, so the Reason (R) is true.

Red light has a longer wavelength ($$\approx 620-750$$ nm) than blue light ($$\approx 450-490$$ nm). Since $$\beta \propto \lambda$$, red light produces wider fringes, not closer fringes. Therefore the Assertion (A) is false.

Hence, (A) is false but (R) is true, which corresponds to Option 4.