The fringe width (\( \beta \)) in a double-slit experiment is given by: \[ \beta = \frac{\lambda D}{d}, \] where: - \( \lambda \) is the wavelength of the light, - \( D \) is the distance between the slits and the screen, - \( d \) is the separation between the slits.
Step 1: Relation between fringe widths. Since \( D \) and \( d \) are constant, the fringe width \( \beta \) is directly proportional to \( \lambda \): \[ \beta \propto \lambda. \]
Step 2: Calculate the new fringe width. Let the initial fringe width (\( \beta_1 \)) correspond to \( \lambda_1 = 400 \, \text{nm} \) and the new fringe width (\( \beta_2 \)) correspond to \( \lambda_2 = 600 \, \text{nm} \). Then: \[ \frac{\beta_2}{\beta_1} = \frac{\lambda_2}{\lambda_1}. \] Substituting \( \beta_1 = 2 \, \text{mm} \), \( \lambda_1 = 400 \, \text{nm} \), and \( \lambda_2 = 600 \, \text{nm} \): \[ \frac{\beta_2}{2} = \frac{600}{400} \implies \beta_2 = 2 \cdot 1.5 = 3 \, \text{mm}. \]
Final Answer: The fringe width for \( \lambda = 600 \, \text{nm} \) is: \[ \boxed{3 \, \text{mm}}. \]
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,

What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)