When a resistance of 2, ohm is connected across the terminals of a cell, the current is 0.5, A. When the resistance is increased to

Q: When a resistance of $2\, ohm$ is connected across the terminals of a cell, the current is $0.5\, A$. When the resistance is increased to $5\, ohm$, the current is $0.25\, A$. The $e.m.f.$ of the cell is ................. $V$

b Since $i\, = \left( {\frac{E}{{R + r}}} \right),$ we get $0.5 = \frac{E}{{2 + r}}$ ...... $(i)$ $0.25 = \frac{E}{{5 + r}}$ ..... $(ii)$ Dividing $(i)$ by $(ii)$, we get $2 = \frac{{5 + r}}{{2 + r}}$ $ \Rightarrow $ $r = 1\,\Omega $ $0.5 = \frac{E}{{2 + 1}}$ $ \Rightarrow $ $E = 1.5\,V$

SECTION - A [PHYSICS - MCQ]

GSEB - English Medium

When a resistance of $2\, ohm$ is connected across the terminals of a cell, the current is $0.5\, A$. When the resistance is increased to $5\, ohm$, the current is $0.25\, A$. The $e.m.f.$ of the cell is ................. $V$

A$1$
B$1.5$
C$2$
D$2.5$

Medium

STD 11 Science
NEET
STD 12 - 3. current electricity
Physics

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.*

Download App

Similar Questions

1
In order to determine the $e.m.f.$ of a storage battery it was connected in series with a standard cell in a certain circuit and a current $I_1$ was obtained. When the battery is connected to the same circuit opposite to the standard cell a current $I_2$ flow in the external circuit from the positive pole of the storage battery was obtained. What is the $e.m.f$. $\varepsilon_1$ of the storage battery? The $e.m.f$. of the standard cell is $\varepsilon_2$.
View Solution
2
$A$ conductor is made of an isotropic material and has shape of a truncated cone. $A$ battery of constant emf is connected across it and its left end is earthed as shown in figure. If at a section distant $x$ from left end, electric field intensity, potential and the rate of generation of heat per unit length are $E, V$ and $H$ respectively, which of the following graphs is are correct?
View Solution
3
The equivalent resistance between the points $A$ and $D$ ................ $\Omega$
View Solution
4
In the circuit shown in figure, the resistance of voltmeter is $6\, k\Omega $. The voltmeter reading will be ................. $\mathrm{V}$
View Solution
5
The resistance of the series combination of two resistance is $S$. When they are joined in parallel the total resistance is $P$. If $S = nP$, then the minimum possible value of $n$ is
View Solution
6
In the given circuit, the terminal potential difference of the cell is:
View Solution
7
Electric current has both magnitude and direction. It is a
View Solution
8
In the circuit shown in figure, the power which is dissipated as heat in the $6\,\Omega $ resistor is $6\,W$. What is the value of resistance $R$ in the circuit? ................ $\Omega$
View Solution
9
In given figure, the potentiometer wire $AB$ has a resistance of $5$ $\Omega$ and length $10\, m$. The balancing length $AM$ for the $emf$ of $0.4\, V$ is ............... $m$
View Solution
10
If resistivity of all four wire connected in parallel is different as given in figure and all other dimensions of wire are same then current $i$ is (resistance of wire having resistivity $\rho $ is $R_0$ )
View Solution

Download our appand get started for free

Similar Questions

Download our app
and get started for free