Current Electricity

Is NCERT enough for Current Electricity in JEE?

NCERT is close to sufficient for JEE Main here: Ohm's law, Kirchhoff's rules, the Wheatstone bridge, the metre bridge and the potentiometer are asked almost directly. Add complex-circuit reduction and RC-circuit practice for Advanced.

Common JEE questions on Current Electricity

How do I apply Kirchhoff's laws without sign mistakes?

Fix a loop direction, take potential drop as negative across a resistor when moving with the current, and positive across a cell from − to +. Stay consistent in every loop.

What is the balance condition of a Wheatstone bridge?

P/Q = R/S. At balance the galvanometer current is zero, so that branch can be removed — a common JEE shortcut.

Why is a potentiometer more accurate than a voltmeter?

At the null point it draws no current from the cell being measured, so it reads the true EMF.

How does temperature affect resistance?

For metals R = R₀(1 + αΔT), so resistance rises with temperature; for semiconductors it falls.