Two wires P and Q of same length and material but radii in the ratio 2...
Using Hooke ‘s Law we get
Stress directly proportional to stress = Load/Area=F/pie*r*r
And rp:rq=2:1
When both the wires are under the same stress,strain produced will be the same.
When both the wires are under the same stress,strain produced will be the same.
2.when both the wires are loaded by same weight then
Strain p/strain q=(rq)2/(rp)2=¼
View all questions of this test
Two wires P and Q of same length and material but radii in the ratio 2...
Given:
- Two wires P and Q of same length and material
- Radii of wires P and Q are in the ratio 2:1
To find:
- Ratio of strain produced in the wires when both are under the same force
Strain is defined as the ratio of change in length to the original length of a wire. It is given by the formula:
Strain = change in length / original length
Let's assume the original length of both wires P and Q is L.
The change in length of a wire is directly proportional to the force applied and inversely proportional to the cross-sectional area of the wire. Mathematically, it can be expressed as:
Change in length ∝ Force / Cross-sectional area
As both wires are made of the same material, the Young's modulus (a measure of stiffness) is the same for both wires.
Let's calculate the cross-sectional area of wire P and wire Q:
- Let the radius of wire P be 2r
- Therefore, the radius of wire Q will be r (as per the given ratio)
- The cross-sectional area of wire P = π(2r)^2 = 4πr^2
- The cross-sectional area of wire Q = π(r)^2 = πr^2
Now, let's consider the force applied to both wires to be F.
The change in length of wire P can be calculated using the formula:
Change in length of wire P = (F * L) / (4πr^2 * Y) ... (1)
where Y is the Young's modulus of the material.
Similarly, the change in length of wire Q can be calculated using the formula:
Change in length of wire Q = (F * L) / (πr^2 * Y) ... (2)
Taking the ratio of equation (1) and equation (2), we get:
Strain in wire P / Strain in wire Q = [(F * L) / (4πr^2 * Y)] / [(F * L) / (πr^2 * Y)]
= [(F * L) / (4πr^2 * Y)] * [(πr^2 * Y) / (F * L)]
= 1/4
Therefore, the ratio of strain produced in wire P to wire Q is 1:4.
Hence, the correct answer is option (c) 1:4.