A non-zero current passes through the galvano | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B, D) Let the battery voltage be $V = 10 \ V$. When the key $K$ is open, the circuit is a series-parallel combination. The equivalent resistance is $

Vedclass · Accepted Answer

The galvanometer resistance is $150 \ \Omega$.

Vedclass · Answer

(B, D) Let the battery voltage be $V = 10 \ V$. When the key $K$ is open, the circuit is a series-parallel combination. The equivalent resistance is $R_{eq} = (200 + 300) \parallel (100 + G) = \frac{500(100+G)}{600+G}$. The current through the galvanometer branch is $I_{G, open} = \frac{V}{100+G}$.When the key $K$ is closed, the circuit becomes a Wheatstone bridge. The condition that the current through the galvanometer does not change means the bridge is balanced, i.e.,$\frac{200}{100} = \frac{300}{G}$.Solving for $G$: $G = \frac{300 	imes 100}{200} = 150 \ \Omega$. Thus, option $D$ is correct.With $G = 150 \ \Omega$, the current through the galvanometer when the key is closed is $I_{G, closed} = \frac{V}{R_{eq}'}$. Since the bridge is balanced, the potential at the two ends of the galvanometer is the same, and the current is determined by the potential divider: $I_G = \frac{10}{100+150} = \frac{10}{250} = 0.04 \ A = 40 \ mA$. Thus, option $B$ is correct.Since the bridge is balanced, the ratio of resistances in the arms is equal, so the currents in the upper and lower branches are independent of the galvanometer connection, but the current through $200 \ \Omega$ is not necessarily equal to the current through $300 \ \Omega$ unless the resistances are equal. Here $200 \ \Omega 
eq 300 \ \Omega$, so option $C$ is incorrect.

$A$ non-zero current passes through the galvanometer $G$ shown in the circuit when the key $K$ is closed and its value does not change when the key is opened. Then, which of the following statement$(s)$ is/are true?

Similar Questions

Determine the current in each branch of the network shown in Figure.

Refer to the figure given below. The values of $I_1, I_2$ and $I_3$ are . . . . . . .

In the following circuit,the current $I_3$ is

In a Wheatstone bridge (see figure),resistances $P$ and $Q$ are approximately equal. When $R = 400 \,\Omega$,the bridge is balanced. On interchanging $P$ and $Q$,the value of $R$ for balance is $405 \,\Omega$. The value of $X$ is close to ................. $\Omega$. (in $.5$)

The figure shows a network of five resistances and two batteries. The current through the $15\,V$ battery is .............. $A$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module