Karnataka Board-2018

State Kirchoff's laws of electrical network.

Obtain the expression for the effective emf and the effective internal resistance of two cells connected in parallel such that the currents are flowing in the same direction.

$100 mg$ mass of nichrome metal is drawn into a wire of area of cross-section $0.05 m{m}^2$. Calculate the Resistance of the wire Given the density of nichrome $8.4\times {10}^3 kg{m}^{-3}$ and resistivity of the material is  $1.2\times {10}^{-6 }\Omega m$ .

Define electrical resistivity of a material.

Write the expression for drift velocity in terms of current, explain the terms used.

Two cells of emf $E_1$ and $E_2$, internal resistance $r_1$ and $r_2$ are connected in parallel such that they send current in same direction. Derive an expression for equivalent resistance and equivalent emf of the combination.

Two resistors are connected in series with $5 \mathrm{V}$ battery of negligible internal resistance. A current of $2 \mathrm{A}$ flows through each resistor, if they are connected in parallel with the same battery a current of $\frac{25}{3} \mathrm{A}$ flows through combination. Calculate the value of each resistance.

Derive the expression for the conductivity of a material where the terms have their usual meaning.