The energy of an electron in the \( n \)-th Bohr orbit is given by the formula: \[ E_n = \frac{-13.6 \, \text{eV}}{n^2}. \] For the first orbit (\( n = 1 \)): \[ E_1 = \frac{-13.6}{1^2} = -13.6 \, \text{eV}. \] For the third orbit (\( n = 3 \)): \[ E_3 = \frac{-13.6}{3^2} = \frac{-13.6}{9} = -1.51 \, \text{eV}. \] Hence, the energy in the third orbit is \( \frac{1}{9} \) of the energy in the first orbit.
Given below are two statements:
Statement (I) : The dimensions of Planck’s constant and angular momentum are same.
Statement (II) : In Bohr’s model, electron revolves around the nucleus in those orbits for which angular momentum is an integral multiple of Planck’s constant.
In the light of the above statements, choose the most appropriate answer from the options given below:
In the following \(p\text{–}V\) diagram, the equation of state along the curved path is given by \[ (V-2)^2 = 4ap, \] where \(a\) is a constant. The total work done in the closed path is: 
Let \( ABC \) be a triangle. Consider four points \( p_1, p_2, p_3, p_4 \) on the side \( AB \), five points \( p_5, p_6, p_7, p_8, p_9 \) on the side \( BC \), and four points \( p_{10}, p_{11}, p_{12}, p_{13} \) on the side \( AC \). None of these points is a vertex of the triangle \( ABC \). Then the total number of pentagons that can be formed by taking all the vertices from the points \( p_1, p_2, \ldots, p_{13} \) is ___________.
Consider the following two reactions A and B: 
The numerical value of [molar mass of $x$ + molar mass of $y$] is ___.