# Thermal Stress

## Trending Questions

**Q.**18.The tension in the string connected between the blocks is

**Q.**A brass wire 1.8 m long at 27 °C is held taut with little tension between two rigid supports. If the wire is cooled to a temperature of –39 °C, what is the tension developed in the wire, if its diameter is 2.0 mm ? Co-efficient of linear expansion of brass = 2.0 × 10¯⁵ K¯¹; Young’s modulus of brass = 0.91 × 10¹¹ Pa.

**Q.**Three capillaries of length l.l/2, l/3 are connected in series.Their radii are r, r/2, r/3 respectively.Then if stream line flow is to be maintained and the pressure across the first capillary is P then

**Q.**when a tension F is applied in uniform wire of length l and radius r, the elongation produced is e.when tension 2F is applied, the elongation produced in another uniform wire of length 2l and radius 2r made of same material is

**Q.**6.Tension T in the string connecting 10 kg and 5 kg blocks (as shown in the figure) is [g = 10 m/s]

**Q.**12.A wire of length L suspended vertically from a rigid support is made to suffer extension "l" in its length by applying force F. Work is

**Q.**An iron rod of length 1 m is fixed between two walls as shown in figure. Find thermal stress and thermal strain developed in the rod if it is heated by ΔT=20∘C

(Given: Coefficient of linear expansion of iron is 1.2×10−5 ∘C−1; Young's modulus of iron is 2×1011 N/m2).

- 24×107 N/m2, 48×10−5
- 48×106 N/m2, 32×10−4
- 32×107 N/m2, 48×10−4
- 48×106 N/m2, 24×10−5

**Q.**59 An elastic spring has length l(1) when tension in it is 4 N . Its length is l(2) when tension in it is 5N . What will be its length when tension in it is 9 N.?

**Q.**There is some change in length when a 33000 N tensile force is applied on a steel rod of area of cross section 10−3 m2. The change of temperature required to produce the same elongation, if steel rod is heated, is: (The modulus of elasticity is 3×1011 N/m2 and the coefficient of linear expansion of steel is 1.1×10−5∘C−1)

- 10∘C
- 1∘C
- 20∘C
- 30∘C

**Q.**There is some change in length when a 33, 000 N tensile force is applied on a steel rod of area of cross-section 10−3 m2. The change of temperature required to produce the same elongation, if the steel rod is heated, is -

[Take modulus of elasticity Y=3×1011N/m2 and the coefficient of linear expansion of steel is α=1.1×10−5/∘C]

- 20∘C
- 15∘C
- 10∘C
- 0∘C

**Q.**23.Find tension in the string and acce ration

**Q.**A metal bar of length 1 m and area of cross-section 1 mm2 is clamped between two rigid supports. For the material of rod, its Young's modulus is Y=1011 N/m2 and coefficient of linear expansion is α=1.8×10−5 ∘C−1. If the temperature of the rod is decreased by ΔT=10∘C, the force exerted by the rod on the supports is

- 9 N
- 6 N
- 16 N
- 18 N

**Q.**A rod of length l and radius r is held between two rigid walls so that it is not allowed to expand. If its temperature is increased , then the force developed in it is proportional to

**Q.**

Which of the following arrangements of a wire clamped on two walls will cause an additional stress within the wire?

- A piece of wire clamped between two clamps is heated up
- A piece of wire clamped between two clamps is cooled down
Both (a) and (b)

Neither (a) nor (b)

**Q.**

A barometer kept in an elevator reads 76 cm when it is at rest. If the elevator goes up with increasing speed, the reading will be

zero

76 cm

< 76 cm

> 76 cm

**Q.**

A uniform steel wire of cross-sectional area 0.20 mm2 is held fixed by clamping its two ends. Find the extra force exerted by each clamp on the wire if the wire is cooled from 100∘C to 0∘C. Young's modulus of steel = 2.0 × 1011 N/m2. Coefficient of linear expansion of steel = 1.2 × 10−5/∘C.

- 500 N
- 480 N
- 4.8 N
- 48 N

**Q.**A bar of uniform cross-section and having a length l is hanging from the roof. What will be the elongation in bar due to self weight if γ is the specific weight of the bar and Y is the young's modulus of elasticity?

**Q.**

In the given figure, a rod is free at one end and other and is fixed. When we change the temperature of rod by ΔT, then strain produced in the rod will be

αΔT

12αΔT

- zero
- information incomplete

**Q.**A steel rod of length 1 m is fixed between two walls. If the rod is heated from 25oC to 35o C, the stress developed in the rod is expressed as x×107 N/m2. Find the value of x.

(coefficient of expansion for steel is 2×10−5/∘C, Young's modulus of steel is 2×1011 N/m2)

- 2
- 4
- 7
- 8

**Q.**A steel rod of length 5 m and diameter 30 mm is fixed between two rigid supports. Determine the thermal stress and change in diameter of the rod, when the temperature increases by 50 ∘C. Take Young's modulus of elasticity (Y)=2.0×106 kg/cm2, coefficient of thermal expansion (α)=12×10−6 /∘C and Poisson's ratio (ν)=0.3.

- 120 kg/cm2, 0.0234 mm
- 1200 kg/cm2, 0.018 mm
- 12000 kg/cm2, 0.0054 mm
- 1200 kg/cm2, 0.0234 mm

**Q.**Consider a wire of length l, radius r, breaking stress s and breaking strength b, then what happens to breaking stress and breaking strength if, L (new length) and r (new radius) respectively equal: (i) 2l, r ;(ii) 2l, r/2; (iii) 2l, 2r ;(iv)l, r ;(v)l, r/2 ;(vi)l, 2r ;(vii)l/2, r ;(viii)l/2, r/2 ; (ix) l/2, 2r