The energy stored in the capacitor after closing the key K is
When the key \( K \) is closed, the energy stored in a capacitor is given by the formula: \[ U = \frac{1}{2} C V^2 \] where:
- \( U \) is the energy stored,
- \( C \) is the capacitance of the capacitor,
- \( V \) is the voltage across the capacitor.
Hence, the energy stored in the capacitor after closing the key \( K \) is \( \frac{1}{2} CV^2 \).
Therefore, the correct answer is (C).
The equivalent capacitance of the circuit given between A and B is
If $ X = A \times B $, $ A = \begin{bmatrix} 1 & 2 \\-1 & 1 \end{bmatrix} $, $ B = \begin{bmatrix} 3 & 6 \\5 & 7 \end{bmatrix} $, find $ x_1 + x_2 $.