(a) Two batteries of emf's $3\text{V}$ & $6\text{V}$ and internal resistances $0.2\,\Omega$ & $0.4\,\Omega$ are connected in parallel. This combination is connected to a $4\,\Omega$ resistor. Find : (i) the equivalent emf of the combination (ii) the equivalent internal resistance of the combination (iii) the current drawn from the combination OR (b) (i) A conductor of length $l$ is connected across an ideal cell of emf $\text{E}$. Keeping the cell connected, the length of the conductor is increased to $2l$ by gradually stretching it. If $\text{R}$ and $\text{R}'$ are initial and final values of resistance and $\text{v}_\text{d}$ and $\text{v}_\text{d}'$ are initial and final values of drift velocity, find the relation between (i) $\text{R}'$ and $\text{R}$ and (ii) $\text{v}_\text{d}'$ and $\text{v}_\text{d}$. (ii) When electrons drift in a conductor from lower to higher potential, does it mean that all the 'free electrons' of the conductor are moving in the same direction ?

Year	Paper Code	Set	Position
CBSE 2025	Series 55-1	Set 1	Question 22
CBSE 2025	Series 55-1	Set 2	Question 22
CBSE 2025	Series 55-1	Set 3	Question 22

• Step 1: Stating the fundamental formula / law statement (+1 Mark)
• Step 2: Intermediate mathematical substitution or proof steps (+1 Mark)
• Step 3: Correct final value or conclusion with mandatory SI units (+1 Mark)