The circuit shown here is used to compare the emf of two cells $E_1$ and $E_2 (E_1 > E_2)$. The null point is at $C$ when the galvanometer is connected to $E_1$. When the galvanometer is connected to $E_2$, the null point will be
Ato the left of $C$
Bto the right of $C$
Cat $C$ itself
D
no change in null point
Easy
Download our app for free and get started
Ato the left of $C$
a In case of potentiometer, $\mathrm{E}_{1} / \mathrm{E}_{2}=l_{1} / l_{2} .$ As given that $\mathrm{E}_{1}>\mathrm{E}_{2},$ therefore $l_{1}>l_{2} .$ Therefore, the null point for the cell of $\mathrm{emf}$ $\mathrm{E}_{2}$ must be at shortest length than that of cell $\mathrm{E}_{1} .$ Thus, the null point on potentiometer wire should shift towards left of $\mathrm{C}$
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.*
The $H$ amount of thermal energy is developed by a resistor in $10\,s$ when a current of $4\,A$ is passed through it. If the current is increased to $16\,A$, the thermal energy developed by the resistor in $10\,s$ will be $........\,H$
Water boils in an electric kettle in $20$ minutes after being switched on. Using the same main supply, the length of the heating element should be. . . . . . .to . . . . . .. times of its initial length if the water is to be boiled in $15$ minutes.
Two batteries of $e.m.f.$ $4\,V$ and $8 \,V$ with internal resistances $1\, \Omega$ and $2\,\Omega$ are connected in a circuit with a resistance of $9 \,\Omega$ as shown in figure. The current and potential difference between the points $P$ and $Q$ are
A copper wire of diameter $1.02\, mm$ carries a current of $1.7\, amp$. Find the drift velocity $(v_d)$ of electrons in the wire. Given $n$, number density of electrons in copper $= 8.5 \times 10^{27} /m^3$....................... $mm/sec$
A potentiometer wire $PQ$ of $1\,m$ length is connected to a standard cell $E _{1}$. Another cell $E _{2}$ of emf $1.02\, V$ is connected with a resistance $'r'$ and switch $S$ (as shown in figure). With switch $S$ open, the null position is obtained at a distance of $49\, cm$ from $Q$. The potential gradient in the potentiometer wire is.......$V/cm$