Answer the question all
A 40W-110V bulb is to be used with 220V-50Hz AC.Calculate the inductance required for this purpose.
or
(c) In a diffraction phenomenon, radius of the central bright region is given as ${\mathrm{r}}_0=\frac{1.22\mathrm{\lambda f}}{2\mathrm{a}}$
$$\begin{gathered} \mathrm{where} \mathrm{\lambda } \mathrm{is} \mathrm{wavelength} \mathrm{of} \mathrm{the} \mathrm{light},\mathrm{f} \mathrm{is} \mathrm{the} \mathrm{focal} \mathrm{length} \mathrm{of} \mathrm{the} \mathrm{lens} \mathrm{used} \mathrm{and} 2\mathrm{a} \mathrm{is} \mathrm{the} \\ \mathrm{diameter} \mathrm{of} \mathrm{the} \mathrm{aperture}.\mathrm{Show} \mathrm{that} \mathrm{in} \mathrm{order} \mathrm{to} \mathrm{observe} \mathrm{two} \mathrm{objects} \mathrm{clearly} \mathrm{by} \mathrm{a} \mathrm{microscope}, \\ \mathrm{the} \mathrm{minimum} \mathrm{separation} \mathrm{between} \mathrm{them} \mathrm{must} \mathrm{be} \frac{1.22\mathrm{\lambda }}{2\mathrm{sin\beta }} \mathrm{where} \mathrm{\beta } \mathrm{is} \mathrm{the} \mathrm{angle} \mathrm{between} \mathrm{principal} \\ \mathrm{axis} \mathrm{of} \mathrm{the} \mathrm{objective} \mathrm{and} \mathrm{the} \mathrm{ray} \mathrm{of} \mathrm{light} \mathrm{from} \mathrm{the} \mathrm{object} \mathrm{to} \mathrm{the} \mathrm{apex} \mathrm{of} \mathrm{the} \mathrm{lens}. \end{gathered}$$
or
$$\begin{gathered} \mathrm{A} \mathrm{beam} \mathrm{of} \mathrm{light} \mathrm{consisting} \mathrm{of} \mathrm{wavelengths} 6500\dot{\mathrm{A}} \mathrm{and} 5200\dot{\mathrm{A}} \mathrm{is} \mathrm{used} \mathrm{in} \mathrm{Young}\text{'}\mathrm{s} \mathrm{double} \mathrm{slit} \\ \mathrm{experiment} \mathrm{of} \mathrm{slit} \mathrm{separations} 2\mathrm{mm} \mathrm{and} \mathrm{where} \mathrm{the} \mathrm{screen} \mathrm{is} 120 \mathrm{cm} \mathrm{away}.\mathrm{Find} \mathrm{the} \mathrm{distance} \\ \mathrm{to} \mathrm{the} \mathrm{third} \mathrm{fringe} \mathrm{from} \mathrm{the} \mathrm{central} \mathrm{maximum} \mathrm{for} \mathrm{the} \mathrm{wavelength} 6500\dot{\mathrm{A}}. \mathrm{What} \mathrm{is} \mathrm{the} \mathrm{least} \\ \mathrm{distance} \mathrm{from} \mathrm{the} \mathrm{central} \mathrm{maximum} \mathrm{at} \mathrm{which} \mathrm{the} \mathrm{bright} \mathrm{fringes} \mathrm{due} \mathrm{to} \mathrm{both} \mathrm{wavelengths} \\ \mathrm{coincide}? \end{gathered}$$