EXERCISES

A heating element using Nichrome connected to a $230 \mathrm{V}$ supply draws an initial current of $3.2 \mathrm{A}$ which settles after a few seconds to a steady state value of $2.8 \mathrm{A}$. What is the steady state of heating element if the room temperature is $27 °\mathrm{C}$? Temperature coefficient of resistance of Nichrome averaged over temperature range involved is $1.70\times {10}^{-4} {\mathrm{C}}^{-1}$.

Determine the current in each branch of the network shown in the given figure

In a meter bridge shown in the figure, the balance point is found to be at $39.5 \mathrm{cm}$ from the end $A$ when the resistor $Y$ is of $12.5 \mathrm{\Omega }$. Determine the resistance of $X$. Why are the connections between resistors in a Wheatstone or meter bridge made of thick copper strips?

In a meter bridge shown in the figure, the balance point is found to be at $39.5 \mathrm{cm}$ from the end A when the resistor X is of $8.16 \mathrm{\Omega }$ and Y is of $12.5 \mathrm{\Omega }.$

Determine the balance point of the bridge above, if X and Y get interchanged.

In a meter bridge shown in the figure, the balance point is found to be at $39.5 \mathrm{cm}$ from the end $\mathrm{A}$ when the resistor $\mathrm{X}$ is of $8.2 \mathrm{\Omega }$ and $\mathrm{Y}$ is of $12.5 \mathrm{\Omega }$.
What happens if the galvanometer and cell are interchanged at the balance point of the bridge? Would the galvanometer show any current?

A storage battery of emf $8.0 \mathrm{V}$ and internal resistance $0.5 \mathrm{\Omega }$ is being charged by a $120 \mathrm{V}$ dc supply using a series resistor of $15.5 \mathrm{\Omega }.$ What is the terminal voltage of the battery during charging? What is the purpose of having a series resistor in the charging circuit?

In a potentiometer arrangement, a cell of emf $1.25 \mathrm{V}$ gives a balance point at $35.0 \mathrm{cm}$ length of the wire. If the cell is replaced by another cell and the balance point shifts to $63.0 \mathrm{cm}$, what is the emf of the second cell?

The number density of free electrons in a copper conductor estimated is  $8.5\times {10}^{28} {\mathrm{m}}^{-3}$. How long does an electron take to drift from one end of a wire $3.0 \mathrm{m}$ long to its other end? The area of cross-section of the wire is  $2.0\times {10}^{-6} {\mathrm{m}}^2$ and it is carrying a current of  $3.0 \mathrm{A}$. Take, charge of electron, $e =1.6\times {10}^{-19} \mathrm{C}$.