TN State Board 12th Physics Question Paper 2024

A solar cell is a device that converts light energy directly into electrical energy. This process is based on the photovoltaic effect, where the absorption of photons generates electron-hole pairs in a semiconductor, creating a potential difference. Diffusion, carrier flow, and recombination are physical processes occurring within a semiconductor device, but the overarching principle of energy conversion in a solar cell is photovoltaic action.

For an electromagnetic wave in vacuum, the relationship between the amplitude of the electric field ($E_0$) and the amplitude of the magnetic field ($B_0$) is given by $E_0 = c B_0$, where $c$ is the speed of light in vacuum ($c \approx 3 \times 10^8 \text{ m/s}$). Given $B_0 = 3 \times 10^{-6} \text{ T}$, we calculate: $E_0 = (3 \times 10^8 \text{ m/s}) \times (3 \times 10^{-6} \text{ T}) = 9 \times 10^2 \text{ V/m} = 900 \text{ V/m}$. Thus, option (c) is correct. Options (a), (b), and (d) are incorrect because they do not satisfy the fundamental wave relation $E_0/B_0 = c$.

The power $P$ dissipated by a resistor is given by the formula $P = \frac{V^2}{R}$. Given $V = 240\ V$ and $R = 120\ \Omega$, we have $P = \frac{240^2}{120} = \frac{57600}{120} = 480\ W$. Therefore, 480 W is the correct choice.

The ionization potential of an H-like atom for the ground state ($n=1$) is given by $E_n = 13.6 \times Z^2$ eV. Given $E_1 = 122.4\ V$, we have $122.4 = 13.6 \times Z^2$. Dividing both sides, $Z^2 = \frac{122.4}{13.6} = 9$. Thus, $Z = \sqrt{9} = 3$. The atomic number is 3.

Polarisation is the phenomenon that confirms the transverse nature of light waves. Longitudinal waves (like sound) cannot be polarized, whereas light waves can be, proving that the vibrations of the electric field vector are perpendicular to the direction of propagation. Scattering, interference, and diffraction occur for both longitudinal and transverse waves.