Question

A wire of lamp 1m has a resistance of 2ohm when connected to a cell the current in the wire is 3 ampere now a 2 metre length of the wire is connected to the same cell what is the resistance of the wires and current in it

Answer 1

for the 1m lamp:
Resistance= Resistivity × (Length ÷ Cross-sectional area)

that is, 2 ohm= resistivity × (1 ÷ Cross-sectional area)

Now, assuming that the wires are made of the same material and has the same cross-sectional area:

2 ohm ÷ 1 m = X ohm ÷ 2 m [here, X is the resistance of the second wire.

from here, the second wire's resistance comes as 4 ohms.

now, since the CELL is the SAME, the VOLTAGE will be the same.

we know, V=IR where V is the voltage, I is the current and R is the resistance.

Since the voltage remains constant,

3 amp × 2 ohm = I amp × 4 ohm [here, I amp is the current in the second wire]

From here, the current in the second wire comes as 1.5 amp.

I know it's pretty big a sum, but it helps going step-by-step. Hope this helped!