Question
Physics Question on Current electricity
Dimensions of a block are 1cm�1cm�100cm. If specific resistance of its material is 3×10−7Ωm, then the resistance between the opposite rectangular faces is
A
3×10−7Ωm
B
3×10−9Ωm,
C
3×10−5Ωm,
D
3×10−3Ωm,
Answer
3×10−7Ωm
Explanation
Solution
Here length l=1cm=10−2m
Area of cross-section, A=1cm×100cm
=100cm2
=10−2m2
Resistance, R=ρAℓ=3×10−7×10−210−2
=3×10−7Ω