Question

Assertion: The current flowing through each resistor is the same when connected in series.
Reason: The voltage drop across each resistor remains the same when connected in parallel.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is the incorrect
D. Both Assertion and Reason are incorrect.

Answer 1

Hint: So the given question, we have an assertion which is the current flowing through each resistor is the same when connected in series and the reason is given is the voltage drop across each resistor remains the same when connected in parallel. Now we know that, in the case of series, current remains constant. So by using ohm's law i.e. $V=IR$, if I is constant then $V\alpha R$ and this implies that there will be voltage across each resistor.

Complete answer:
We have been provided with an assertion which is the current flowing through each resistor is the same when connected in series and the reason is given is the voltage drop across each resistor remains the same when connected in parallel. Let’s consider a circuit having three resistance connected in series and I be the current flows through it and in this now we know that, in case of series, current is constant.

Assertion: Current flows in a circuit. In other words, it's the rate of flow of electric charges with time. Other than $i=\dfrac{dq}{dt}$ ​, current is also given by $I=nAE{{v}_{d}}$,​ which says something which is depends upon the drift velocity of electrons. The drift velocity is nothing but the average velocity between two successive collisions. This velocity prevents the electrons from accelerating continuously.
Let's consider a circuit with three resistors with resistances in an increasing order which are ${{R}_{1}}$​; ${{R}_{2}}$​; ${{R}_{3}}$​. First, current enters into ${{R}_{1}}$ ​. After some collisions, it exits the resistor. Now, the same current enters and exits through ${{R}_{2}}$​ and ${{R}_{3}}$​,​ in the same manner. The rate of flow of charges is always the same. Only the drift velocities vary according to different resistors. If the same are connected in parallel, current flows through ​${{R}_{3}}$easily(Now, we look into the resistors), because, ${{R}_{3}}$​​ requires a lesser ${{v}_{d}}$​ i.e. electrons entering ${{R}_{3}}$​​ would exit within a small period of time relative to the other two and as a result, larger current would be observed.
Reason: Voltage is simply the energy per unit charge in both electrostatics and current electricity. Let's assume that the electrons have some amount of energy and they pass through the series of resistors. When the electrons encounter collisions within the resistor ${{R}_{1}}$​, they lose their potential which is also referred to as "voltage drop" accordingly with their drift velocity i.e. number of collisions which evolves as heat and the remaining potential is still present in those electrons which drops across other resistors present. Thus, the sum of each potential drop gives the total potential in that particular circuit. As in case of parallel circuits, current is generally divided. Now, though the charges are taking different paths, they have the same potential energy. Hence, the potential drop across each resistor would be the same, therefore assertion and Reason both are correct but Reason is not the correct explanation for Assertion.

So, the correct answer is “Option B”.

Note:
When current flows in the direction opposite to the direction of flow of current, electrons travel. While travelling, electrons collide and cause heat generation. Generation of heat depends upon the resistance of each. The current entered and exited the resistors with the same magnitude, in case of series.