A wire of length $5\,m$ and radius $1\,mm$ has a resistance of $1\, ohm$. What length of the wire of the same material at the same temperature and of radius $2\,mm$ will also have a resistance of $1\, ohm$ .............. $m$
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A cell of $emf$ $E$ and internal resistance $r$ is connected in series with an external resistacne $nr.$ Then, the ratio of the terminal potential difference to $emf$ is
A $5\,^oC$ rise in temperature is observed in a conductor by passing a current. When the current is doubled the rise in temperature will be approximately ........... $^oC$
A potentiometer has uniform potential gradient. The specific resistance of the material of the potentiometer wire is $10^{-7} \, ohm-meter$ and the current passing through it is $0.1\, ampere$; cross-section of the wire is $10^{-6}\, m^2$. The potential gradient along the potentiometer wire is
What length of the wire of specific resistance $48 \times {10^{ - 8}}\,\Omega \,\,m$ is needed to make a resistance of $4.2 \, \Omega$ .............. $m$ (diameter of wire = $0.4\, mm$)
A wire of resistance $12\,ohms$ per meter is bent to form a complete circle of radius $10\, cm.$ The resistance between its two diametrically opposite points, $A$ and $B$ as shown in the figure is
Figure $(i)$ below shows a Wheatstone's bridge in which $P, Q, R$ and $S$ are fixed resistances, $G$ is a galvanometer and $B$ is a battery. For this particular case, the galvanometer shows zero deflection. Now, only the positions of $B$ and $G$ are interchanged, as shown in figure $(ii)$. The new deflection of the galvanometer
A cylindrical conductor has uniform cross-section. Resistivity of its material increase linearly from left end to right end. If a constant current is flowing through it and at a section distance $x$ from left end, magnitude of electric field intensity is $E$, which of the following graphs is correct