Current Electricity - Electromagnetism - Physics Previous Year Questions

Find the current in the three resistors as shown in the following figure?

The resistivity of a material is found to be $10^8 \Omega-\mathrm{m}$, then the material would be

A cylindrical metallic wire is stretched to increase its length in such a way that the metallic wire changes its resistance by $6 \%$. The percentage increase in its length is

Balancing point of a potentiometer shifts from a length of 60 cm to 40 cm by shunting the cell with a $4 \Omega$ resistance. What is the internal resistance of the cell?

A metal wire of length $L$ and radius $r$ has a resistance $R$. If a wire of the same metal of length $2 L$ and radius $3 r$ is taken, then what will be its resistance?

Two wires made of the same material have lengths in the ratio $2: 3$ and radii in the ratio $8: 9$. If the same potential difference is applied across the ends of the wires, the ratio of the electric currents flowing through them is

A potentiometer balances at 44 cm when a cell of internal resistance $1 \Omega$ is in the secondary circuit. To obtains the balancing point at 40 cm , the resistance to be connected parallel to cell is

If the masses of three wires of same material are in the ratio of $1: 2: 3$ and their lengths are in the ratio of $3: 2: 1$, then electrical resistances of these wires are in the ratio

As shown in the figure, in a Wheatstone's bridge, three resistances $P, Q$ and $R$ are connected in the three arms and the fourth arm is formed by two resistances $S_1$ and $S_2$ connected in parallel. The condition for the bridge to be balanced is

In a meter bridge experiment the ratio of the left gap resistance to the right gap resistance is $2: 3$. The balance length from left end is

The electric resistance of a certain wire of iron is $R$. If its length and radius are both doubled, then

In a galvanometer, $5 \%$ of the total current in the circuit passes through it. If the resistance of the galvanometer is $G$, the shunt resistance $S$ connected to the galvanometer is

A uniform conducting wire $A B$ of length 5 m and resistance $5 \Omega$ is connected as shown in the circuit. If the balancing point is obtained at 3 m from $A$, then the value of $E$ is

In the given circuit, the equivalent resistance between $A$ and $B$ is

A wire of resistance $2 R$ is stretched such that its length is doubled. Then the increase in its resistance is

The Wheatstone bridge shown in the diagram is balanced. If $P_3$ is the power dissipated by $R_3$ and $P_1$ is the power dissipated by $R_1$, then the ratio $P_3 / P_1$ is

Find the current in the circuit.

A cylindrical wire $P$ has resistance $10 \Omega$. A second wire $Q$ has length and diameter half that of $P$. If the material of both the wires is same, then resistance of wire $Q$ is

If the Wheatstone's bridge with four resistors $R_1, R_2$ and $R_3, R_4$ is balanced, then the correct expression is

A conductor of length 100 cm and area of cross-section $1 \mathrm{~mm}^2$ carries a current of 5 A . If the resistivity of the material of the conductor is $3.0 \times 10^{-8} \Omega-\mathrm{m}$, then the electric field across the conductor is