Edexcel A Level Physics Paper 2: Advanced Physics II November 2020 question paper 9PH0/02

Which row of the table shows a base quantity and its base SI unit?

The diagram shows binding energy per nucleon against nucleon number for atomic nuclei.

Which line of the table correctly identifies the process that would increase stability for nuclei in the positions indicated by X and Y?

When a force F is applied to a spring with stiffness k, the elastic potential energy stored is E.

What is the elastic potential energy stored when a force 2F is applied to a spring with stiffness 2 k ?

There are several different methods that can be used to determine the distance from our solar system to astronomical objects. These include the measurement of red shift, trigonometrical parallax and the use of standard candles.

Which row of the table shows a suitable method for each of the objects named?

A damped mass-spring system is driven into oscillation. The graph shows the amplitude of oscillation as the driving frequency is varied.

The damping is decreased.

Which row of the table describes what happens to the maximum amplitude of oscillation and the driving frequency at which this occurs?

A proton can be considered to be both a point charge and a point mass. There is an electric field and a gravitational field associated with the proton.

Which of the following statements about the fields is not correct?

A pendulum of length l with a bob of mass m oscillates with frequency f.

What is the frequency of a pendulum of length 4l with a bob of mass 2m?

Which of the following lenses would produce a real image of an object placed 15 cm away from the lens?

A detector is placed 30 cm from a gamma source, the count rate is 64 counts per minute.

The detector is then placed 60 cm from the source. The background rate is presumed to be a constant 24 counts per minute.

Which of the following gives the expected counts per minute?

A cup contains 180 g of black coffee at a temperature of 82 °C. 68 g of milk at a temperature of 2.7 °C is added to the coffee. An ideal temperature range for drinking coffee is said to be 50 °C to 60 °C.

Deduce whether the coffee will be within the ideal temperature range when the milk is added.

initial temperature of milk = 2.7 °C

specific heat capacity of black coffee = 4.2 × 10³J kg⁻¹K⁻¹

specific heat capacity of milk = 3.9 10³J kg⁻¹K⁻¹

The angle of incidence of the light as it enters the tank is 7.2°

Show that the refractive index of the liquid is about 1.4

w = 35.0 cm t = 4.0 cm s = 10.2 cm

Determine the speed of light in the liquid.

A student measured the deflection of a mass attached to the end of a thin strip of metal. The strip was clamped to a bench at one end as shown.

The student varied the force on the end of the strip by changing the mass attached.

The deflection was measured each time when the mass was in its equilibrium position.

The student obtained the following graph of deflection against force.

State why the mass will oscillate with simple harmonic motion when it is displaced slightly from its equilibrium position and released.

The student then investigated the oscillations of the mass on the metal strip. The student fixed different numbers of 10 g masses to the end of the metal strip.

The student noticed that the smaller the mass the higher the frequency of the oscillations. He estimated that the maximum number of oscillations he could count was two per second. He decided that the smallest mass he should use was 50 g.

Determine whether 50 g is the smallest mass he should use.

You may assume that the system acts in the same way as a mass on a spring.

The photograph shows a filament bulb.

The filament is an emitter with 35% of the power output of a black body radiator of the same temperature.

When a potential difference (p.d) of 2.0 V is applied across the bulb, there is a current of 0.37 A in the filament.

Calculate the temperature of the filament.

surface area of filament = 3.9 × 10⁻⁶m²

In an experiment to investigate the efficiency of a filament light bulb a p.d. was applied. The p.d. and current were measured and the light bulb was observed. The p.d. was then increased and new measurements taken.

When a small p.d. is applied to the bulb, no light is visible. If the p.d. is gradually increased, the filament starts to glow and eventually appears white.

Use your graph to explain why filament light bulbs are considered inefficient.

The photograph shows a guitar.

When a guitar string is plucked, a standing wave is created.

Explain how a standing wave is created on the string.

The diagram shows a standing wave on a guitar string.

The oscillating length of the guitar string is 66 cm.

State the wavelength for this standing wave.

Calculate the frequency of vibration for this standing wave.

tension in guitar string = 88.6 N

mass per unit length of guitar string = 4.47 10⁻³kg m⁻¹

One end of the guitar string is wrapped around a cylindrical tuning peg. Turning the peg changes the total length of the string and hence changes the tension in the string. This changes the frequency of vibration of the string.

The length of one string is 68 cm.

Calculate the extension required to produce a tension of 93.4 N in the string.

Young modulus of string material = 1.8 × 10⁹N m⁻²

cross-sectional area of string = 6.6 10⁻⁷m²

The vibrating length of string is unchanged by turning the tuning peg.

Explain the effect that tightening the string has on the frequency of the sound produced.

Astronauts on the 1971 Apollo 14 mission to the Moon brought back many rock samples. It is now believed that one of these contains a piece of rock that originated on Earth about 4 billion years (4 × 10⁹ years) ago.

The piece of rock is believed to have been launched into space when an asteroid struck the Earth.

The rock sample contains uranium. The radioactive decay of uranium allows it to be used to determine the time since the rock was formed on the Earth.

The uranium isotope²³⁸₉₂U becomes the lead isotope²⁰⁶₈₂Pb through a series of radioactive decays.

Calculate the number of α particles and the number of β particles emitted for one nucleus of²³⁸₉₂U to decay to become a nucleus of²⁰⁶₈₂Pb.

The half-life of²³⁸₉₂U is 4.47 10⁹ years. The half-lives of the other stages in the decay to²⁰⁶₈₂Pb are relatively so short that they can be ignored.

There was no lead in the rock when it formed, so all the²⁰⁶₈₂Pb in the sample is a product of²³⁸₉₂U decay. In the sample, for every 103 uranium nuclei present at the start, 50 are now lead nuclei.

Show that the age of the sample is about 4 × 10⁹ years.

The gravitational potential between the Earth and the Moon due to the combined effect of their gravitational fields increases to a maximum value of −1.28 MJ kg⁻¹ at a point between them.

Calculate the minimum speed at which a rock would have to leave the Earth in order to reach the Moon.

In your calculation, you may assume the rock has zero kinetic energy when it has maximum potential energy.

mass of Earth = 5.97 10²⁴kg radius of Earth = 6370 km

Four billion years ago, the Moon had a different orbital period, because it was closer to the Earth than it is today.

Calculate the period of the Moon’s orbit four billion years ago, when the radius of its orbit was 1.34 10⁸m.

mass of Earth = 5.97 × 10²⁴kg

In 1905 Einstein published his equation for the photoelectric effect.

In 1916 Millikan demonstrated that the maximum kinetic energy of photoelectrons is consistent with Einstein’s equation.

*(a) Discuss the extent to which our current understanding of observations of the photoelectric effect supports the idea that light behaves as photons rather than as waves.

Millikan used his data to obtain a value of the Planck constant.

The following graph of maximum kinetic energy of photoelectrons against frequency was produced from his data for the photoelectric effect using lithium.

Millikan suggested that the uncertainty from his results for lithium was as little as 1%.

Determine whether the value of the Planck constant obtained from this graph is within 1% of the value stated on the data sheet for this examination paper.

Millikan used a device known as a monochromator to ensure that a single wavelength of light was used to illuminate the surface of the lithium. A monochromator separates wavelengths using a diffraction grating.

Calculate the angle at which a diffraction grating would produce the most intense line at a single wavelength of 6.1 × 10⁻⁷m.

number of lines per mm for grating = 600 mm⁻¹

At the Culham Centre for Fusion Energy (CCFE) experiments are carried out to investigate nuclear fusion and the properties of plasmas. A plasma consists of ionised gas, containing positive ions and electrons.

In a fusion experiment at CCFE, ions of two isotopes of hydrogen fuse to produce helium ions and fast-moving neutrons.

Show that a single fusion reaction releases about 3 10⁻¹²J of energy.

mass of₁²H = 2.013553 u mass of₁³H = 3.015501 u mass of⁴₂He = 4.001506 u mass of₀¹n = 1.008665 u

Fusion occurs naturally in the core of stars.

Explain why very high densities of matter and very high temperatures are needed to bring about and maintain nuclear fusion in stars.

In a plasma experiment 5.0 mg of deuterium, an isotope of hydrogen, occupies a volume of 98 m³. The temperature of deuterium is raised to 1.3 10⁸K. In this experiment, the deuterium behaves as an ideal gas.

Calculate the pressure due to the deuterium ions.

mass of deuterium ion = 3.3 10⁻²⁷kg

Calculate the root mean square speed of the deuterium ions at this temperature.

The temperature of the plasma is monitored using the Doppler effect. Light from a laser is directed into the plasma and the wavelength of the light reflected is measured.

The Doppler shift observed when light is reflected by a deuterium ion is twice the Doppler shift that would be observed for a source of light moving at the same speed as the deuterium ion.

Calculate the maximum wavelength of light that would be detected after reflection from a deuterium ion moving at 1.5 × 10⁶m s⁻¹.

wavelength of laser light = 1064 nm