Four ammeters with identical internal resistance $r$ and a resistor $R$ are connected to a current source as given. if reading of $A_1$ and $A_2$ is $3\ A$ and $5\ A$ respectively then the reading $A_4$ is ............. $A$
A$1$
B$3$
C$5$
D$7$
Medium
Download our app for free and get started
D$7$
d $\mathrm{V}_{1}=5 \mathrm{\,r}$
$\mathrm{V}_{2}=3 \mathrm{\,r}$
$\mathrm{V}_{1}-\mathrm{V}_{2}=2 \mathrm{\,r}$
curront in middle one is $2 \mathrm{\,A}$ so reading should be $7 \mathrm{\,A}$
Download our app
and 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.*
Two batteries $V_1$ and $V_2$ are connected to three resistors as shown below. If $V_1=2 \,V$ and $V_2=0 \,V$, then the current $I=3 \,mA$. If $V_1=0 \,V$ and $V_2=4 \,V$, then the current $I=4 \,mA$. Now, if $V_1=10 \,V$ and $V_2=10 \,V$, then the current $I$ will be ............ $\,mA$
In 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 .............. $\Omega$
A piece of fuse wire melts when a current of $15\, ampere$ flows through it. With this current, if it dissipates $22.5\, W$, the resistance of fuse wire will be .............. $\Omega$
A resistor dissipates $192\, {J}$ of energy in $1\, {s}$ when a current of $4\, {A}$ is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in $5 \,{s}$ in $.....\,J.$
Resistance are connected in a meter bridge circuit as shown in the figure. The balancing length $l_{1}$ is $40\,cm$. Now an unknown resistance $x$ is connected in series with $P$ and new balancing length is found to be $80\,cm$ measured from the same end. Then the value of $x$ will be $.......\Omega$
During an experiment with a metre bridge, the galvanometer shows a null point when the joceky is pressed at $40.0 \ cm$ using a standard resistance of $90 \ \Omega$, as shown in the figure. The least count of the scale used in the meter bridge is $1 \ mm$. The unknown resistance is:
A torch bulb rated as $4.5\, W, 1.5\, V$ is connected as shown in the figure. The $e.m.f.$ of the cell needed to make the bulb glow at full intensity is ............. $V$