A copper cylindrical tube has inner radius a and outer radius b- The resistivity is - The resistance of the cylinder between the two rends is-

A body of density $ρ$ sinks in a liquid of density $ρ_{L}$ . The densities $ρ$ and $ρ_{L}$ , are related as :
(a) $ρ$ = $ρ_{L}$ (b) $ρ$ < $ρ_{L}$
(c) $ρ$ > $ρ_{L}$ (d) nothing can be said.

Find the resistance of a hollow cylinder of inner radius a and outer radius b whose inner and outer cylindrical surfaces are connected by to a p.d ( $ρ$ resistivity)

Q. We know resistance is given by the equation,

R = \frac{ρ l}{A}

So, for a resistor of a particular material, if the resistance is doubled, by what factor does

ρ

change?

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A copper cylindrical tube has inner radius a and outer radius b. The resistivity is ρ. The resistance of the cylinder between the two rends is?

The correct option is B ρlπ(b2−a2)R=ρlA=ρlπ(b2−a2)A=πb2−πa2=π(b2−a2)

A copper cylindrical tube has inner radius a and outer radius b. The resistivity is $ρ$ . The resistance of the cylinder between the two rends is?

The correct option is B $\frac{ρ l}{π (b^{2} - a^{2})}$
$R = \frac{ρ l}{A} = \frac{ρ l}{π (b^{2} - a^{2})} A = π b^{2} - π a^{2} = π (b^{2} - a^{2})$