AP EAPCET 18 May 2024 Shift 1 Solved Paper

To find the resistivity of the potentiometer wire, we are provided with the following information:
Area of cross-section (A): 4cm2=4×10−4m2
Current (i): 1 A
Potential Gradient (‌

V

l

):7.5V∕m
We need to calculate the resistivity ( ρ ) of the wire.
Calculation:
From Ohm's law, we know the following relationship:
V=i⋅R
The resistance R for a wire can be expressed in terms of its resistivity:
R=ρ‌

l

A

Thus, substituting R in the equation for V :
V=i⋅‌

ρl

A

Rearranging this equation to solve for resistivity ( ρ ):
ρ=‌

V

l

⋅‌

A

i

Substitute the known values:
ρ=(7.5V∕m)⋅(‌

4×10−4m2

1A

)
Calculate ρ :
ρ=‌

7.5×4×10−4

1

‌ρ=30×10−4
‌ρ=3×10−3Ω−m
Therefore, the resistivity of the potentiometer wire is 3×10−3Ω−m.