The refraction at a spherical surface is governed by the equation: \[ \frac{\mu_2}{v} - \frac{\mu_1}{u} = \frac{\mu_2 - \mu_1}{R}, \] where:
\( \mu_1 = 1.0 \) (refractive index of the rarer medium),
\( \mu_2 = 1.5 \) (refractive index of the denser medium),
\( u = -15 \, \text{cm} \) (object distance, negative as it is measured opposite to the direction of incident light),
\( R = +30 \, \text{cm} \) (radius of curvature, positive as the center of curvature lies in the denser medium),
\( v \) is the image distance to be determined.
Substitute the values into the equation: \[ \frac{1.5}{v} - \frac{1.0}{-15} = \frac{1.5 - 1.0}{30}. \]
Simplify: \[ \frac{1.5}{v} + \frac{1}{15} = \frac{0.5}{30}. \] \[ \frac{1.5}{v} = \frac{1}{60} - \frac{1}{15}. \]
Simplify further: \[ \frac{1.5}{v} = \frac{1 - 4}{60} = \frac{-3}{60}. \] \[ \frac{1.5}{v} = -\frac{1}{20}. \] Solve for \( v \): \[ v = -\frac{1.5 \cdot 20}{1} = -30 \, \text{cm}. \] The negative sign indicates that the image is formed on the opposite side of the refracting surface, i.e., in the denser medium.
Final Answer: The distance of the image from the pole of the surface is: \[ \boxed{30 \, \text{cm}}. \]
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 : \(A_2 \rightleftharpoons 2A\)