Alternating Current — Physics STD 12 Science — Question

When a lens is dipped into the water its focal length :

Assertio : Hydrogen atom consists of only one electron but its emission spectrum has many lines.  
Reason  : Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found. (a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

Rydberg’s constant is:

A vertical wire carries a current in upward direction. An electron beam sent horizontally towards the wire will be deflected:

The unit for molar susceptibility is

In the experiment of diffraction at a single slit, if the slit width is decreased, the width of the central maximum(a) Increases in both Fresnel and Fraunhofer diffraction(b) Decreases both in Fresnal and Fraunhofer diffraction (c) Increases in Fresnel diffraction but decreases in Fraunhofer diffraction(d) Decreases in Fresnel diffraction but increases is Fraunofer diffraction.

Two parallel pillars are 11 km away from an observer. The minimum distance between the pillars so that they can be seen separately will be(a) 3.2 m(b) 20.8 m(c) 91.5 m(d) 183 m