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A 2.00-kg copper rod is 50.00 cm long at 23°C. If 40 000 J are transferred to the rod by heat, what is its change in length? ccopper = 387 J/kg·°C and αcopper = 17 × 10-6/°C.

a. 0.022 cm
b. 0.044 cm
c. 0.059 cm
d. More information is needed

Respuesta :

Answer:

0.044 cm

Explanation:

mass of copper, m = 2 kg

length of rod, l = 50 cm

T1 = 23°C

Heat, Q = 40000 J

specific heat of copper, c = 387 J/kg°C

α = 17 x 10^-6 /°C

Let the change in the length of copper is Δl.

heat = mass x specific heat x ΔT

40000 = 2 x 387 x ΔT

ΔT = 51.68

Now use the formula for the linear expansion

Δl = l x α x ΔT

Δl = 50 x 17 x 10^-6 x 51.68

Δl = 0.044 cm

Thus the increase in length of rod is 0.044 cm.

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