[Maximum number: 4]

A thermometer and an electrical heater are inserted into small holes in a solid aluminium block.

The heater is turned on at time t=0. The graph shows the variation of the temperature $\theta$ of the block with time t.

(a)

Suggest why the temperature of the block approaches a constant value.

[ 2 ]

(b)

The power of the heater is 52 W . The mass of the block is 0.85 kg . Determine the specific heat capacity of aluminium.

[ 2 ]

[Maximum number: 4]

A thermometer and an electrical heater are inserted into small holes in a solid aluminium block.

The heater is turned on at time t=0. The graph shows the variation of the temperature $\theta$ of the block with time t.

(a)

Suggest why the temperature of the block approaches a constant value.

[ 2 ]

(b)

The power of the heater is 52 W . The mass of the block is 0.85 kg . Determine the specific heat capacity of aluminium.

[ 2 ]

[Maximum number: 4]

A thermometer and an electrical heater are inserted into small holes in a solid aluminium block.

The heater is turned on at time t=0. The graph shows the variation of the temperature $\theta$ of the block with time t.

(a)

Suggest why the temperature of the block approaches a constant value.

[ 2 ]

(b)

The power of the heater is 52 W . The mass of the block is 0.85 kg . Determine the specific heat capacity of aluminium.

[ 2 ]

[Maximum number: 4]

A thermometer and an electrical heater are inserted into small holes in a solid aluminium block.

The heater is turned on at time t=0. The graph shows the variation of the temperature $\theta$ of the block with time t.

(a)

Suggest why the temperature of the block approaches a constant value.

[ 2 ]

(b)

The power of the heater is 52 W . The mass of the block is 0.85 kg . Determine the specific heat capacity of aluminium.

[ 2 ]

[Maximum number: 4]

Two students investigate the variation with temperature $\theta$ of the resistance R of a copper wire. The plastic covered copper wire is wrapped around a mercury-in-glass thermometer and immersed in a beaker of water.

The students allow the water to cool slowly from $95^{\circ} \mathrm{C}$ .
The students measure the resistance of the wire and the temperature of the water at the same instant.

Their results are shown with error bars for R. Errors in $\theta$ can be ignored.

(a)

The students suggest that R is given by $R=R_{0}(1+\alpha \theta)$ .

[ 4 ]

(i)

Deduce $\alpha$ . State an appropriate unit for $\alpha$ .

[ 4 ]

[Maximum number: 2]

A group of students is trying to determine the density and the viscosity of a liquid.

To determine the density, they use a balance to read the mass m of a sphere in air and immersed in the liquid.

They use a sphere of volume $V=1.827 \times 10^{-7} \mathrm{~m}^{3}$ .
The readings are $m_{\text {air }}=1.427 \mathrm{~g}$ in air and $m_{\text {lmmersed }}=1.208 \mathrm{~g}$ in the liquid.
The readings are different due to buoyancy. The buoyancy force $F_{\mathrm{b}}$ is given by

F_{\mathrm{b}}=\rho V g

where V is the volume of the sphere and $\rho$ is the density of the liquid.

(a)

Calculate the density of the liquid.

[ 2 ]

[Maximum number: 2]

A student is analysing a sample of water. To determine its density, the student measures the volume with a measuring cylinder and the mass with an electronic balance.

(a)

Suggest whether the water sample can be considered pure.

[ 2 ]

[Maximum number: 2]

A group of students is trying to determine the density and the viscosity of a liquid.

To determine the density, they use a balance to read the mass m of a sphere in air and immersed in the liquid.

They use a sphere of volume $V=1.827 \times 10^{-7} \mathrm{~m}^{3}$ .
The readings are $m_{\text {air }}=1.427 \mathrm{~g}$ in air and $m_{\text {lmmersed }}=1.208 \mathrm{~g}$ in the liquid.
The readings are different due to buoyancy. The buoyancy force $F_{\mathrm{b}}$ is given by

F_{\mathrm{b}}=\rho V g

where V is the volume of the sphere and $\rho$ is the density of the liquid.

(a)

Calculate the density of the liquid.

[ 2 ]

[Maximum number: 7]

This question is about stars in the constellation Canis Minor.

(a)

Define absolute magnitude.

[ 2 ]

(b)

Luyten's star and Gomeisa are two stars associated with the constellation Canis Minor. The table gives data for these stars and for the Sun.

[ 1 ]

(i)

State, in parsecs, the distance range over which it is possible to use the spectroscopic parallax technique to measure galactic distances.

[ 1 ]

(c)

(i)

Using the data in (c), calculate, in parsecs, the distance from Earth to Gomeisa.

[ 3 ]

(d)

Gomeisa, Luyten's star and the Sun are main sequence stars. On the grid of the Hertzsprung-Russell (HR) diagram, identify the position of

[ 1 ]

(i)

Gomeisa, with the letter G.

[ 1 ]

(a)

Aldebaran is a red giant star in the constellation of Taurus.

[ 4 ]

(i)

Define the luminosity of a star.

[ 1 ]

(ii)

The apparent brightness of Aldebaran is $3.3 \times 10^{-8} \mathrm{Wm}^{-2}$ and the luminosity of the Sun is $3.9 \times 10^{26} \mathrm{~W}$ . The luminosity of Aldebaran is 370 times that of the Sun. Show that Aldebaran is at a distance of 19 pc from Earth. $\left(1 \mathrm{pc}=3.1 \times 10^{16} \mathrm{~m}\right)$

[ 3 ]

(b)

The apparent magnitude of Aldebaran is 0.75 .

[ 3 ]

(i)

State what is meant by the apparent magnitude of a star.

[ 1 ]

(ii)

Use the answer to (a)(iii) to determine the absolute magnitude of Aldebaran.

[ 2 ]

(c)

Distances to galaxies may be determined by using Cepheid variable stars.

By considering the nature and properties of Cepheid variable stars, explain how such stars are used to determine galactic distances.

[ 5 ]