A rubber ball filled with water, having a small hole is used as the bob of a simple pendulum. The time period of such a pendulum

The ratio of wavelengths for transition of electrons from $$2^{\text {nd }}$$ orbit to $$1^{\text {st }}$$ orbit of Helium $$\left(\mathrm{He}^{++}\right)$$ and Lithium $$\left(\mathrm{Li}^{++1}\right)$$ is (Atomic number of Helium $$=2$$, Atomic number of Lithium $$=3$$ )

For an intrinsic semiconductor $$\left(\mathrm{n}_{\mathrm{h}}\right.$$ and $$\mathrm{n}_{\mathrm{e}}$$ are the number of holes per unit volume and number of electrons per unit volume respectively)

A $$5.0 \mathrm{~V}$$ stabilized power supply is required to be designed using a $$12 \mathrm{~V}$$ DC power supply as input source. The maximum power rating of zener diode is $$2.0 \mathrm{~W}$$. The minimum value of resistance $$R_{\mathrm{s}}$$ in $$\Omega$$ connected in series with zener diode will be