To calculate the separation distance between two consecutive bright fringes on the screen, we can use the equation:
d*sin(theta) = m * lambda
Where:
- d is the separation distance between the double slits (1.00 mm in this case)
- theta is the angle of diffraction of the bright fringe
- m is the order of the bright fringe (1 for the first order, 2 for the second order, etc.)
- lambda is the wavelength of the sodium lighting (5.9x10^-5 cm in this case)
a) Let's calculate the separation distance between two consecutive bright fringes using the formula mentioned above:
Using the given values:
- d = 1.00 mm = 0.1 cm
- lambda = 5.9x10^-5 cm
We can rearrange the formula to solve for theta:
theta = arcsin(m * lambda / d)
For the first-order bright fringe (m = 1):
theta = arcsin(1 * 5.9x10^-5 cm / 0.1 cm)
Now, we can calculate the angle:
theta ≈ 0.059 radians
To find the separation distance between two consecutive bright fringes on the screen, we can use the approximation:
Separation distance = m * wavelength * screen distance / d
For the first-order bright fringe (m = 1):
Separation distance ≈ 1 * 5.9x10^-5 cm * 100 cm / 0.1 cm
Separation distance ≈ 0.59 cm ≈ 0.59 mm
Therefore, the separation distance between two consecutive bright fringes on the screen is approximately 0.59 mm.
b) If the sodium lighting is replaced with a BLUE monochromatic source, the wavelength will be different. The wavelength of blue light is generally shorter than that of sodium light. As a result, the diffraction pattern on the screen will change. The bright fringes will be closer together because the smaller wavelength leads to a larger angle of diffraction.
In summary, if the sodium lighting is replaced with a blue monochromatic source, the separation distance between the consecutive bright fringes on the screen will decrease compared to the previous case with sodium lighting.