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In a flow calorimeter, heat is supplied at a steady rate to a liquid flowing through it, and the steady-state temperature rise between inflow and outflow is measured to find the liquid's specific heat. A liquid of density 0.2 g/cm³ flows at 10 cm³/s. A 250 W coil supplies the heat, and a steady temperature difference of 25 deg C is established. Find the specific heat of the liquid.
- 1 cal g⁻¹ deg C⁻¹
- 2 cal g⁻¹ deg C⁻¹
- 3 cal g⁻¹ deg C⁻¹
- 4 cal g⁻¹ deg C⁻¹
Correct answer: 1 cal g⁻¹ deg C⁻¹
Solution
Mass flow = 0.2*10 = 2 g/s; c = P/(mdot*deltaT) = 5000/(2*25) = 100 J/g... = ~1.19 cal/g/deg C, closest to 1.
Related JEE Advanced Physics questions
- Match the temperature of a blackbody listed in Group-I to the corresponding statement in Group-II, and select the correct answer.
[Given: Wien’s constant = 2.9 × 10⁻³ m-K and hc/e = 1.24 × 10⁻⁶ V-m]
Group-I:
(P) 2000 K
(Q) 3000 K
(R) 5000 K
(S) 10000 K
Group-II:
(1) The peak wavelength of emitted radiation can cause photoelectron ejection from a metal with a work function of 4 eV.
(2) The peak wavelength of emitted radiation falls within the visible spectrum.
(3) The peak wavelength of emitted radiation produces the broadest central diffraction maximum in a single-slit setup.
(4) The energy radiated per unit area is one-sixteenth of that emitted by a blackbody at 6000 K.
(5) The peak wavelength of emitted radiation is suitable for imaging human bones.
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- A continuous-flow calorimeter is used in two separate experiments to find the specific heat of a liquid. In the first trial, supplying 60 W raises the liquid temperature by 10 K. In the second trial, the power is doubled to 120 W, but the same 10 K rise is maintained by tripling the flow rate. Assuming heat loss to surroundings is the same in both trials, what is the power lost to the surroundings?
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