two metal rods A and B have their initial length in the ratio 2:3 and coefficients of linear expansion in the ratio of 4:3. when they are heated through same temperature difference the ratio of their linear expansion is
Correct answer: D. 8:9
- A. 1:2
- B. 2:3
- C. 3:4
- D. 8:9
Explanation
Here's how to solve this problem and find the ratio of their linear expansions:1. Define variables:Let L_A and L_B be the initial lengths of rods A and B, respectively.Let α_A and α_B be the coefficients of linear expansion of rods A and B, respectively.Let ΔT be the same temperature difference for both rods.Let ΔL_A and ΔL_B be the linear expansions of rods A and B, respectively.2. Use the formula for linear expansion:ΔL = α * L * ΔT3. Apply the information given:L_A / L_B = 2 / 3 (ratio of initial lengths)α_A / α_B = 4 / 3 (ratio of coefficients of linear expansion)ΔT is the same for both rods (given in the problem)4. Find the ratio of linear expansions (ΔL_A / ΔL_B):Substitute the given information into the formula for linear expansion for both rods:ΔL_A = α_A * L_A * ΔTΔL_B = α_B * L_B * ΔTDivide both equations:(ΔL_A / ΔL_B) = (α_A * L_A * ΔT) / (α_B * L_B * ΔT)Since ΔT cancels out and the ratio of coefficients remains 4/3, we only need to consider the ratio of initial lengths:(ΔL_A / ΔL_B) = (L_A / L_B) * (α_A / α_B)(ΔL_A / ΔL_B) = (2/3) * (4/3)5. Simplify the equation:(ΔL_A / ΔL_B) = 8/9
Last updated
About Thermal Equilibrium and Heat
Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.
Practise Thermodynamics
714 free Thermodynamics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 15 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
100 W heater is switched on for 5 minutes to melt ice. What is the mass of ice that melts at 0oC? ( The specific latent heat of fusion of ice is 334 J/g).
100 W heater is used for 5 minutes to heat 500 g of water. What is the change in the temperature of the water? (The specific heat capacity of water is 4.2 J/gC).
100 W heater is used to melt 50 g of ice at 0°C. How long should the heater be switched on? (Specific latent heat of fusion of ice is 334 J/g)
100 W heater is used to melt 50 g of ice at OC. How long should the heater be switched on? (Specific latent heat of fusion of ice is 334 J/g)
100W heater is used for 5 minutes to heat 500g of water. What is the change in the temperature of water? (Specific heat capacity of water is 4.2 J/gC)