If Resistance R = 10 ohms of a wire is stretched to double its length, then find new resistance.

The expression for a wire’s resistance can be illustrated as:

R = ρ l/A

Here,

ρ = Resistivity of a material
l = Length of wire
A = Cross-sectional area

Since length of the wire is doubled, then the cross-sectional area becomes half of its last value because volume of the given wire remains constant.

Now, the new cross-sectional area will become:

A′ = A/2

Now, the new resistance of the wire is given as: R′ = ρl′/A′

Now, after replacing the values in the formula, we can obtain:

⇒ R′ = 4ρ l/A

With further division of new resistance with last resistance, we get:

⇒ R′/R = 4

⇒ R′ = 4R

⇒ R = 10

Hence, R’ = 40Ω

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If Resistance R = 10 ohms of a wire is stretched to double its length, then find new resistance.

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Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

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If Resistance R = 10 ohms of a wire is stretched to double its length, then find new resistance.

Related Questions

CBSE CLASS XII Related Questions

3.Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

4.With the help of a labelled diagram, explain the principle, construction and working of an a.c. generator.

5.Write two advantages of reflecting telescope over refracting telescope.

6.Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

3.
Derive an expression for the capacitance of a parallel plate capacitor of plate area A and plate separation d with air present between the plates.

4.
With the help of a labelled diagram, explain the principle, construction and working of an a.c. generator.

5.
Write two advantages of reflecting telescope over refracting telescope.

6.
Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?