The particulate nature of matterIB Physics HL: Topic test

20 questions, 54 marks

IB Physics HL

The particulate nature of matter topic test

Total 54 marks

Name

Class

Date

1
In a school experiment, 20 g of steam at 100°C is passed into 800 g of water initially at 15°C, held in an insulated copper calorimeter of negligible heat capacity. All the steam condenses and the resulting water reaches a final common temperature. The specific heat capacity of water is 4200 J kg⁻¹ K⁻¹ and the specific latent heat of vaporization of water is 2.26 × 10⁶ J kg⁻¹.
(a)
How much energy is released as the 20 g of steam condenses to water at 100°C?
[1 mark]
A4.52 × 10⁴ J
B8.4 × 10³ J
C5.04 × 10⁴ J
D1.81 × 10⁶ J
(b)
Which contributes more to warming the 800 g of water: the latent heat released as the steam condenses, or the heat released as the resulting 20 g of water then cools from 100°C to the final temperature?
[1 mark]
AThe condensed water cooling from 100°C contributes more energy
BThe latent heat released as the steam condenses contributes far more energy (about eight times as much)
CThey contribute exactly equal amounts of energy
DNeither process transfers energy to the water, since the final temperature is below 100°C
(c)
Calculate the final common temperature reached by the water.
[2 marks]
Total for question 1: 4 marks
2
A weather balloon is released at ground level, where the atmospheric pressure is 1.01 × 10⁵ Pa, the temperature is 288 K and the balloon's volume is 2.00 m³. The balloon is sealed, so no gas can enter or leave it. It rises to an altitude where the pressure has fallen to 0.35 × 10⁵ Pa and the temperature is 218 K.
(a)
What is the volume of the balloon at this altitude?
[1 mark]
A5.8 m³
B1.5 m³
C4.4 m³
D0.92 m³
(b)
How does the number of gas molecules inside the balloon change as it rises?
[1 mark]
AIt increases as the balloon expands
BIt decreases because some gas escapes at low pressure
CIt falls to zero once the pressure is low enough
DIt stays constant, since the balloon is sealed and no gas enters or leaves it
(c)
Calculate the amount of gas, in moles, inside the balloon.
[2 marks]
Total for question 2: 4 marks
3
A battery of emf 9.0 V and negligible internal resistance is connected to two resistors, R₁ = 20 Ω and R₂ = 30 Ω, connected in parallel with each other. This parallel combination is connected in series with a third resistor, R₃ = 15 Ω, to complete the circuit.
(a)
Calculate the total resistance of the circuit and the total current drawn from the battery.
[3 marks]
(b)
Calculate the current in each of R₁ and R₂, and the total power dissipated in the whole circuit.
[4 marks]
Total for question 3: 7 marks
4
A fixed amount of 0.40 mol of a monatomic ideal gas undergoes a two-stage process. In stage 1, the gas is heated at constant volume from 300 K to 500 K. In stage 2, starting from the state reached at the end of stage 1, the gas expands at constant pressure until its volume has doubled.
(a)
State the name of the process undergone in stage 1, explain why no work is done on or by the gas during this stage, and calculate the change in internal energy and the energy transferred to the gas as heat during stage 1.
[6 marks]
(b)
Using the ideal gas law, determine the temperature of the gas at the end of stage 2, and hence calculate the work done by the gas and the energy transferred to the gas as heat during stage 2.
[6 marks]
Total for question 4: 12 marks
5
A hypothetical airless exoplanet orbits its star at a distance where the solar constant (the intensity of starlight arriving before any reflection) is 800 W m⁻². The planet has an albedo of 0.20. It absorbs this radiation over its projected cross-sectional area (πr²) and, in thermal equilibrium, radiates as a black body from its entire spherical surface area (4πr²).
(a)
What fraction of the incident starlight does the planet absorb?
[1 mark]
A0.80
B0.20
C1.20
D0
(b)
Which equation correctly expresses the planet's radiative energy balance in equilibrium?
[1 mark]
AS × πr² = σT⁴ × πr²
BS(1 − albedo) × πr² = σT⁴ × 4πr²
CS × 4πr² = σT⁴ × 4πr²
DS(1 − albedo) × 4πr² = σT⁴ × πr²
(c)
Calculate the equilibrium surface temperature of the planet.
[2 marks]
Total for question 5: 4 marks
6
A camper's sleeping mat is a layer of foam of thickness 12 mm and area 0.40 m², with thermal conductivity 0.040 W m⁻¹ K⁻¹. It separates the ground, at a steady 2.0°C, from the surface of the camper's sleeping bag, at a steady 34°C.
(a)
What is the rate of thermal energy transfer by conduction through the mat?
[1 mark]
A45.3 W
B0.043 W
C42.7 W
D25.6 W
(b)
Which mechanism of thermal energy transfer is described here?
[1 mark]
AConvection
BRadiation
CEvaporation
DConduction
(c)
Calculate the total thermal energy conducted through the mat during an 8.0-hour night.
[2 marks]
Total for question 6: 4 marks
7
A battery is connected in series with an ammeter and a variable resistor R. When R is set to 8.0 Ω, the ammeter reads 0.50 A. When R is changed to 18 Ω, the ammeter reads 0.25 A.
(a)
Using the two sets of readings, write down the circuit equation ε = I(R + r) for each case and solve them simultaneously to find the internal resistance r and the emf ε of the battery.
[3 marks]
(b)
Calculate the power dissipated in the variable resistor for each of the two settings, and state, with a reason, which setting delivers power to the external resistor more efficiently.
[4 marks]
Total for question 7: 7 marks
8
A star has a surface temperature of 5800 K and a luminosity of 3.85 × 10²⁶ W. An orbiting planet is at a distance of 1.5 × 10¹¹ m from the star. The planet has an albedo of 0.30 and, having no atmosphere, is in radiative equilibrium: it absorbs the star's radiation over its cross-sectional area and radiates as a black body from its full surface area.
(a)
Calculate the wavelength at which the star's emission spectrum peaks, and the apparent brightness (the intensity of the star's radiation) at the distance of the planet.
[6 marks]
(b)
Using your value of the apparent brightness from (a) as the solar constant at the planet's orbit, calculate the planet's equilibrium surface temperature. Comment on how the presence of an atmosphere containing greenhouse gases would change this result.
[6 marks]
Total for question 8: 12 marks

End of questions