(a) Using Gauss's law, deduce an expression for electric field at a point due to a uniformly charged infinite plane thin sheet. (b) Two large thin plane sheets, each having surface charge density $\sigma$, are held close and parallel to each other in air. What is the net electric field at a point (i) inside and (ii) outside, the sheets ? OR (a) Obtain the condition of balance of a Wheatstone bridge. (b) Find net resistance of the network of resistors connected between A and B, as shown in figure. [Diagram]

Year	Paper Code	Set	Position
CBSE 2026	Series 55-1	Set 1	Question 22
CBSE 2026	Series 55-1	Set 2	Question 24
CBSE 2026	Series 55-1	Set 3	Question 25

• 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)