Physics Modern Physics questions from JEE Main 2015.
A $2V$ battery is connected across $AB$ as shown in the figure. The value of the current supplied by the battery when in first case battery's positive terminal is connected to $A$ and in second case when positive terminal of battery is connected to $B$ will respectively be: 
As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion
De-Broglie wavelength of an electron accelerated by a voltage of $50 \text{V}$ is close to $(|e|=1.6\times {10}^{-19} C, {m}_{e}=9.1\times {10}^{-31} kg, h=6.6\times {10}^{-34} J s)$
If one were to apply the Bohr model to a particle of mass $'m'$ and charge $'q'$ moving in a plane under the influence of a magnetic field 'B', the energy of the charged particle in the ${n}^{th}$ level will be:
In an unbiased p - n junction electrons diffuse from n-region to p-region because:
The de-Broglie wavelength associated with the electron in the $n=4$ level is:
The value of the resistor, ${R}_{S}$, needed in the DC voltage regulator circuit shown here, equals: 