Edexcel A-Level Physics A2 Unit 5 Radiation and Cosmology

Practise Edexcel A-Level Physics A2 Unit 5 with thermodynamics, radiation, oscillations, cosmology, half-life and decay calculations.

Covered syllabus points

5.3 - Thermodynamics 5.4 - Nuclear Decay 5.5 - Oscillations 5.6 - Astrophysics and Cosmology

[Maximum number: 3]

The water in a swimming pool at the Olympic Games should be at a temperature of $28.0^{\circ}\mathrm{C}$ .

A pool contains $2750\,\mathrm{m^3}$ of water at $16.5^{\circ}\mathrm{C}$ .

Calculate the increase in internal energy $\Delta E$ of the water when it is heated to $28.0^{\circ}\mathrm{C}$ .

Density of water $=998\,\mathrm{kg\,m^{-3}}$

Specific heat capacity of water $=4190\,\mathrm{J\,kg^{-1}\,K^{-1}}$

Use ho=m/V, so $m= ho V=(998)(2750)=2.74 imes10^6\,\mathrm{kg}$ . Then

$\Delta E=mc\Delta T=(2.74 imes10^6)(4190)(28.0-16.5)=1.32 imes10^{11}\,\mathrm{J}.$

[Maximum number: 3]

A nucleus of polonium-210 decays to lead-206 by emitting an alpha particle. The masses of the particles are shown in the table.

Table for Question Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 2 — Edexcel A-Level Physics A2

Show that the energy released in the decay is about $9 \times 10^{-13} \mathrm{~J}$ .

The mass defect is $\Delta m=(3.48572-3.41918-0.0664437)\times10^{-25}=9.63\times10^{-30}\,\mathrm{kg}$ . Hence $\Delta E=c^2\Delta m=(3.00\times10^8)^2(9.63\times10^{-30})=8.67\times10^{-13}\,\mathrm J,$ about $9\times10^{-13}\,\mathrm J$ .

[Maximum number: 10]

The photograph shows the 60-storey John Hancock Tower in Boston. This is the tallest building in the state of Massachusetts in the USA.

Shortly after the building was completed in 1976 it was discovered that the wind caused the building to have large amplitude oscillations. To reduce the amplitude, a damper system was installed on the 58th floor.

The damper system consists of a lead box supported between springs, as shown below.

When the lead box is displaced, it moves with damped simple harmonic motion.

Figure for Question Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 3 — Edexcel A-Level Physics A2

(a)

State what is meant by simple harmonic motion.

[ 2 ]

(b)

When the wind blows at a certain speed, the building oscillates with a frequency of 0.17 Hz .

[ 6 ]

(i)

Explain why the damper system should be designed to oscillate at this frequency.

[ 2 ]

(ii)

The dimensions of the lead box are 5.20 m by 5.20 m by 0.90 m .

Calculate the stiffness of the spring system that attaches the lead box to the supports.
density of lead $=11300 \mathrm{~kg} \mathrm{~m}^{-3}$

Stiffness of spring system =

[ 4 ]

(c)

As the floor moves, the rollers force oil through holes in the steel plate.
Explain why this reduces the amplitude of oscillation of the building.

[ 2 ]

[Maximum number: 6]

The diagram shows some equipment that could be used to calibrate a thermistor.

Figure for Question Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 4 — Edexcel A-Level Physics A2

Describe a method a student could use to obtain a calibration curve for the thermistor from $0^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$ .

You should identify any extra equipment that would be needed.

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Covered syllabus points

Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 1

Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 2

Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 3

Question (a)

Question (b)

Question (i)

Question (ii)

Question (c)

Unit 5: Thermodynamics, Radiation, Oscillations and Cosmology question 4