Find the ratio of currents as measured by ammeter in two cases when the key is open and when the key is closed
Medium
Download our app for free and get started
When key is open
$\mathrm{R}_{\mathrm{eq}}=\frac{[\mathrm{R}+2 \mathrm{R}][\mathrm{R}+2 \mathrm{R}]}{\mathrm{R}+2 \mathrm{R}+\mathrm{R}+2 \mathrm{R}}=\frac{9 \mathrm{R}^{2}}{6 \mathrm{R}}=\frac{3 \mathrm{R}}{2}$
$\mathrm{V}=\mathrm{IR} \quad \Rightarrow \mathrm{I}_{1}=\frac{2}{3} \frac{\mathrm{V}}{\mathrm{R}}$
When key is closed
$\mathrm{R}_{\mathrm{eq}}=\frac{\mathrm{R} \times 2 \mathrm{R}}{\mathrm{R}+2 \mathrm{R}}+\frac{\mathrm{R} \times 2 \mathrm{R}}{\mathrm{R}+2 \mathrm{R}}=\frac{4 \mathrm{R}}{3}$
$\mathrm{V}=\mathrm{I}_{2} \mathrm{R} \Rightarrow \mathrm{I}_{2}=\frac{3}{4} \frac{\mathrm{V}}{\mathrm{R}} \Rightarrow \frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=\frac{8}{9}$
Download our appand get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Similar Questions
- 1If a wire of resistance $20\,\Omega $ is covered with ice and a voltage of $210\, V$ is applied across the wire, then the rate of melting of ice is .................. $g/s$View Solution
- 2The effective resistance between $A$ and $B$, if resistance of each resistor is $R$, will beView Solution
- 3Six similar bulbs are connected as shown in the figure with a $DC$ source of $emf\; E$, and zero internal resistance. The ratio of power consumption by the bulbs when $(i)$ all are glowing and $(ii)$ in the situation when two from section $A$ and one from section $B$ are glowing, will beView Solution
- 4In the adjoining circuit, the galvanometer $G$ shows zero deflection. If the batteries $A$ and $B$ have negligible internal resistance, the value of the resistor $R$ will be .............. $\Omega$View Solution
- 5In a potentiometer experiment the balancing with a cell is at length $240\,cm$ . On shunting the cell with a resistance of $2\,\Omega $ , the balancing length becomes $120\, cm$ . The internal resistance of the cell is ................... $\Omega$View Solution
- 6In a meter bridge experiment null point is obtained at $20\, cm$ from one end of the wire when resistance $X$ is balanced against another resistance $Y$. If $X < Y$, then where will be the new position of the null point from the same end, if one decides to balance a resistance of $4X$ against $Y$ ........... $cm$View Solution
- 7In given arrangement $E_1 = 5\, volts$ $E_2 = 7\, volt$ balancing length is $6\,m$ if terminals of $E_2$ are reversed then new balancing length will beView Solution
- 8View SolutionThe amount of heat produced in a resistor when a current is passed through it can be found using
- 9The figure shows a network of resistors and $a$ battery. If $1\,A$ current flowsthrough the branch $CF$, then answer the following questions The current throughView Solution
- 10In the circuit shown here, $E_1 = E_2 = E_3 = 2 V$ and $R_1 = R_2 = 4\,ohms$. The current flowing between points $A$ and $B$ through battery $E_2$ isView Solution
