Question

Which of the following statements is false?
$\left( a \right)$ Kirchhoff’s second law represents energy conservation.
$\left( b \right)$ Wheatstone bridge is the most sensitive when all the four resistance are of the same order of magnitude
$\left( c \right)$ In a balanced Wheatstone bridge, if the cell and the galvanometer are exchanged, the null point is disturbed.
$\left( d \right)$ A rheostat can be used as a potential divider.

Answer 1

Hint : Kirchhoff’s second law can also be known as Kirchhoff’s voltage law. And by using the KVL we can now know the statement justification. If the bridge will be balanced then the null point will not get changed. So for changing the current we can either change the resistance or also we can change the voltage.

Complete Step By Step Solution
$\left( a \right)$True, the sum of voltages in a loop will be equal to zero. Another interpretation is also that whatever energy it produces all gets consumed by resistance. So the conservation of energy can also be represented by Kirchhoff’s voltage law.
$\left( b \right)$ True, if all the four will be equal then there will be no flow of the current and hence it will be most sensitive. So when all the four resistance are of the same order of magnitude then the Wheatstone bridge will be more sensitive.
$\left( c \right)$ False, So on exchanging the galvanometer with the cell, and as we all know there's no modification in null purpose if the cell and also the galvanometer is changed in an exceedingly balanced bridge. Therefore the statement is correct.
$\left( d \right)$True, if a potential is applied and then by sliding the rheostat it can be used as a divider. Therefore a potential divider a rheostat can be used.

Note In physical science, the one which produces an output voltage and that fraction of its input voltage which makes a passive circuit producible and it could be a voltage divider. An easy example of a resistor is two resistors connected asynchronous, with the input voltage applied across the resistance and therefore the output voltage rising from the connection between them.