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Mechanical Properties of Solids appeared 21 times across 3 years — 2.4% of Physics. This question is from Shear Modulus of Elasticity.

Year 2026 2025 2024 Total
Questions 4 9 8 21

Two slabs with square cross section of different materials (1, 2) with equal sides (l) and thickness d₁ and d₂ such that d₂ = 2d₁ and l > d₂. Considering lower edges of these slabs are fixed to the floor, we apply equal shearing force on the narrow faces. The angle of deformation is θ₂ = 2θ₁. If the shear moduli of material 1 is 4 × 10⁹~N/m², then shear moduli of material 2 is x × 10⁹~N/m², where value of x is

Numerical Answer Type:
Enter a numerical value Answer: 1 to 1 +4 marks

Solution & Explanation

Related Formula

Shear modulus definition:

η = Shear StressShear Strain = (F / A)/(θ) = (F)/(Aθ)

where A = l · d is the area of the narrow face parallel to the shearing force F.

Core Logic

We are given:

  • θ₂ = 2θ₁
  • Shearing forces are equal (F₁ = F₂ = F).
  • Thickness relationship: d₂ = 2d₁
  • Resisting face area: A₁ = l d₁ and A₂ = l d₂ = 2l d₁ = 2A₁
  • Shear strain deformation slab configuration layout for Q22 - JEE Main 2025 Morning
    Shear strain deformation slab configuration layout for Q22 - JEE Main 2025 Morning

Step 1: Link Modulus Terms

Express the angular deformation for each slab:

θ₁ = (F)/(l d₁ η₁) θ₂ = (F)/(l d₂ η₂) = (F)/(2l d₁ η₂)

Substitute these expressions into θ₂ = 2θ₁:

(F)/(2l d₁ η₂) = 2 · ((F)/(l d₁ η₁)) (1)/(2η₂) = (2)/(η₁) 4η₂ = η₁ η₂ = (η₁)/(4)
Step 2: Solve for x

Given η₁ = 4 × 10⁹ N/m²:

η₂ = (4 × 10⁹)/(4) = 1 × 10⁹ N/m²

Comparing with η₂ = x × 10⁹ N/m²: x = 1

Pattern Recognition

Shear stress is inversely proportional to the face area parallel to the applied shearing force (A = l · d). Doubling the slab thickness doubles the resisting contact area, halving the applied shear stress under identical lateral loading.

Evaluation Rubric / Model Answer

1

Chapter Mix

Class 11 Physics: Mechanical Properties of Solids

More Mechanical Properties of Solids Previous-Year Questions — Page 5

Q58 jee_main_2024_31_jan_morning Bulk Modulus
The depth below the surface of sea to which a rubber ball be taken so as to decrease its volume by 0.02% is ________ m. (Take density of sea water = 10³ kgm⁻³, Bulk modulus of rubber = 9 × 10⁸ Nm⁻², and g = 10 ms⁻²)
Numerical Answer. Answer: 18 to 18

Solution

Related Formula
β = (-Δ P)/((Δ V)/(V)) Δ P = ρ g h
Core Logic

The change in pressure Δ P is the hydrostatic pressure at depth h.

Δ P = -β (Δ V)/(V) ρ g h = -β (Δ V)/(V)
Step 2: Calculation

Given values: ρ = 10³ kg/m³ g = 10 m/s² β = 9 × 10⁸ N/m² (Δ V)/(V) = -0.02% = -(0.02)/(100)

Substitute into the equation:

10³ × 10 × h = - (9 × 10⁸) × (-(0.02)/(100)) 10⁴ × h = 9 × 10⁸ × 2 × 10⁻⁴ 10⁴ h = 18 × 10⁴ h = 18 m
Chapter Mix

Class 11 Physics: Mechanical Properties Of Solids Class 11 Physics: Mechanical Properties Of Fluids

More Mechanical Properties of Solids Questions — jee_main_2025_04_april_morning

Practice all Mechanical Properties of Solids previous-year questions →

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