List of top Physics Questions on Resistance and Resistivity asked in CBSE CLASS XII

Determine the current in the \( 3 \, \Omega \) branch of a Wheatstone Bridge in the circuit shown in the figure.
A current of \( 4.0 \, \text{A} \) flows through a wire of length \( 1 \, \text{m} \) and cross-sectional area \( 1.0 \, \text{mm}^2 \), when a potential difference of \( 2 \, \text{V} \) is applied across its ends.
Calculate the resistivity of the material of the wire.
An electric iron rated \( 2.2 \, \text{kW}, 220 \, \text{V} \) is operated at \( 110 \, \text{V} \) supply. Find:
its resistance, and
heat produced by it in 10 minutes.
The resistance of a metal wire at \( 20^\circ \text{C} \) is \( 1.05 \, \Omega \) and at \( 100^\circ \text{C} \) is \( 1.38 \, \Omega \). Determine the temperature coefficient of resistivity of this metal.
Derive the condition for which a Wheatstone Bridge is balanced.
The ends of six wires, each of resistance R (= 10 \(\Omega\)) are joined as shown in the figure. The points A and B of the arrangement are connected in a circuit. Find the value of the effective resistance offered by it to the circuit.
The ends of six wires, each of resistance