If the resistance of a conductor is $5\,\Omega\,\,$ at $\,50\,^oC$ and $7\, \Omega\,$ at $\,100\,^oC$ then the mean temperature coefficient of resistance of the material is ............... $^oC$
A$0.008$
B$0.006$
C$0.004$
D$0.001$
Medium
Download our app for free and get started
A$0.008$
a Using ${R_{{T_2}}} = {R_{{T_1}}}[1 + \alpha ({T_2} - {T_1})]$
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 length of a potentiometer wire is $\ell $. A cell of emf $E$ is balanced at a length $\ell /3$ from the positive end of the wire. If the length of the wire is increased by $\ell /2$ at what distance will the same cell give a balanced point
At what rate the potential difference between the plates of a capacitor be changed to set up a displacement current of $1\, A$ in a capacitor of $2\,\mu F$ ?
A uniform metallic wire of length $L$ is mounted in two configurations. In configuration $1$ (triangle), it is an equilateral triangle and a voltage $V$ is applied to corners $A$ and $B$. In configuration $2$ (circle), it is bent in the form of a circle and the potential $V$ is applied at diametrically opposite points $P$ and $Q$. The ratio of the power dissipated in configuration $1$ to configuration $2$ is
In the circuit shown the variable resistance is so adjusted that the ammeter reading is same in both the position $1$ and $2$ of the key. The reading of ammeter is $2A$. If $E = 20V$, then $x$ is :- ................... $\Omega$
A wire of length $L$ and $3$ identical cells of negligible internal resistances are connected in series. Due to current, the temperature of the wire is raised by $\Delta T$ in a time $t$. A number $N$ of similar cells is now connected in series with a wire of the same material and cross-section but of length $2\, L$. The temperature of the wire is raised by the same amount $\Delta T$ in the same time $t$. the value of $N$ is
Consider a block of conducting material ofresistivity '$\rho$' shown in the figure. Current '$I$' enters at '$A$' and leaves from '$D$'. We apply superp osition principle to find voltage '$\Delta V$ ' developed between '$B$' and '$C$'. The calculation is done in the following steps:
$(i)$ Take current '$I$' entering from '$A$' and assume it to spread over a hemispherical surface in the block.
$(ii)$ Calculatefield $E(r)$ at distance '$r$' from $A$ by using Ohm's law $E = \rho j$, where j is the current per unit area at '$r$'.
(iii) From the '$r$' dependence of $E(r)$, obtain the potential $V(r)$ at $r$.
(iv) Repeat $(i), (ii)$ and $(iii)$ for current '$I$' leaving '$D$' and superpose results for '$A$' and '$D$'.
Two resistors are joined in parallel whose, resultant is $\frac{6}{5} \,\Omega$. One of the resistance wire is broken and the effective resistance becomes $2 \,ohms$. Then the resistance (in $ohm$) of the wire that got broken is ..........