Answer:
(a) The second wire will be stretched by 2 mm
(b) The third wire will be stretched by 0.25 mm
Explanation:
Tensile stress on every engineering material is given as the ratio of applied force to unit area of the material.
σ = F / A
Tensile strain on every engineering material is given as the ratio of extension of the material to the original length
δ = e / L
The ratio of tensile stress to tensile strain is known as Young's modulus of the material.

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<u>Part A</u>
cross sectional area and applied force are the same as the original but the length is doubled

The second wire will be stretched by 2 mm
<u>Part B</u>
a third wire with the same length but twice the diameter of the first

e₁ = ¹/₄ x 1 mm = 0.25 mm
The third wire will be stretched by 0.25 mm
The anwser is a even bigger wave is coming
<h3><u>Given </u><u>:</u><u>-</u></h3>
- The mass of the body is doubled
- The height of the body is constant
<h3><u>Solution </u><u>:</u><u>-</u><u> </u></h3>
We know that ,
Potential energy = mgh
<u>Therefore</u><u>, </u>
We can say that,
PE is directly proportional to Mass of the body
<u>According </u><u>to </u><u>the </u><u>question</u><u>, </u>
PE of the body = 2m * g * h. ...eq( I)
From (I) , we can conclude that, If mass of the body get doubled then its PE will also be doubled .
In step 1, to increase the potential energy, the iron will move towards the electromagnet.
In step 2, to increase the potential energy, the iron will move towards the electromagnet.
<h3>Potential energy of a system of magnetic dipole</h3>
The potential energy of a system of dipole depends on the orientation of the dipole in the magnetic field.

where;
is the dipole moment- B is the magnetic field


Increase in the distance (r) reduces the potential energy. Thus, we can conclude the following;
- In step 1, to increase the potential energy, the iron will move towards the electromagnet.
- In step 2, when the iron is rotated 180, it will still maintain the original position, to increase the potential energy, the iron will move towards the electromagnet.
Learn more about potential energy in magnetic field here: brainly.com/question/14383738
Answer:
The resistivity of the wire is 
Explanation:
We have,
Length of a wire is 40 cm or 0.4 m
Diameter of a wire is 0.60 mm
Radius is 0.3 mm or 0.0003 m
Resistance of a wire is 1.5 ohm
Now we need to find the resistivity of the material of which it is made. The resistance of a wire in terms of its resistance, length and area is given by :

= resistivity

So, the resistivity of the wire is
.