A wire of length ' $r$ ' and resistance $100 \Omega$ is divided into $10$ equal parts. The first $5$ parts are connected in series while the next $5$ parts are connected in parallel. The two combinations are again connected in series. The resistance of this final combination is:
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 cells are connected between points $A$ and $B$ as shown. Cell $1$ has emf of $12\,V$ and internal resistance of $3\,\Omega$. Cell $2$ has emf of $6\,V$ and internal resistance of $6\,\Omega$. An external resistor $R$ of $4\,\Omega$ is connected across $A$ and $B$. The current flowing through $R$ will be $.............A$.
In the given circuit of potentiometer, the potential difference $E$ across $AB$ ( $10\, m$ length) is larger than $E _{1}$ and $E _{2}$ as well. For key $K _{1}$ (closed), the jockey is adjusted to touch the wire at point $J_{1}$ so that there is no deflection in the galvanometer. Now the first battery $\left( E _{1}\right)$ is replaced by second battery $\left( E _{2}\right)$ for working by making $K _{1}$ open and $K _{2}$ closed. The galvanometer gives then null deflection at $J _{2}$. The value of $\frac{ E _{1}}{ E _{2}}$ is $\frac{ a }{ b },$ where $a =$ ...............
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 ............. $A$
In the diagram shown, the reading of voltmeter is $20\, V$ and that of ammeter is $4\, A$. The value of $R$ should be (Consider given ammeter and voltmeter are not ideal)
A copper wire has a square cross-section, $2.0\, mm$ on a side. It carries a current of $8\, A$ and the density of free electrons is $8 \times {10^{28}}\,{m^{ - 3}}$. The drift speed of electrons is equal to
The resistance of a wire is $R$. It is bent at the middle by $180^o$ and both the ends are twisted together to make a shorter wire. The resistance of the new wire is