Free CXC Physics Paper 2 January 2021 past paper from 2021. Includes a worked answer key. Open the PDF, take a timed test, and study with AI on Caribbean AI.
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CSEC Physics Paper 2 January 2021 - Free CXC Past Paper with Answers
Free CXC Physics Paper 2 January 2021 past paper from 2021. Includes a worked answer key. Open the PDF, take a timed test, and study with AI on Caribbean AI.
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Every question from this paper as text. See the answers and worked solutions. Questions are the property of the Caribbean Examinations Council; Caribbean AI is not affiliated with CXC.
Figure 1 shows the apparatus which was used by two students to carry out an experiment to determine the focal length, , of a lens by using the object distance, , and the image distance, .
At the end of the experiment the object distance, , and the image distance, , were recorded in Table 1.
| (cm) | (cm) | (cm) | (cm) |
|---|---|---|---|
| 20.0 | 5.0 | 60.0 | 1.6 |
| 30.0 | 3.3 | 30.0 | 3.3 |
| 35.0 | 2.8 | 26.3 | 3.8 |
| 40.0 | 2.5 | 24.0 | 4.2 |
| 45.0 | 2.2 | 22.5 | 4.4 |
| 55.0 | 1.8 | 20.6 | 4.9 |
Complete Table 1 by calculating the missing values.
[6 marks]
On Figure 2 on page 5 plot a graph of against , using 2 cm to represent cm on each axis.
[7 marks]
Use the graph to determine the value of when is cm.
[2 marks]
Use the graph to determine the intercepts, and , on both axes, and calculate the average value, .
[4 marks]
Use the formula to calculate the focal length, , of the lens.
[3 marks]
Complete the following statement:
The principal focus of a concave lens is defined as the 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<![CDATA[[3 marks]
State the 'principle of moments'.
[3 marks]
State another condition that is necessary for a body to be in equilibrium.
[1 mark]
State the formula for the moment of a force, providing the meaning of each variable and its SI unit.
[3 marks]
Figure 3 shows a girl standing on a uniform plank, AB, of length 3 m and weight 270 N. The plank rests on two scales that are located at P and Q, a distance of 2 m apart. The scales are equidistant from the ends of the plank as shown in Figure 3. The scale at P reads 354 N and the scale at Q reads 417 N.
Figure 3. A girl standing on a uniform plank
[4 marks]
On Figure 3, draw and label ALL the forces that are acting on the plank.
[2 marks]
Calculate the girl's weight.
[2 marks]
By taking moments about Q, calculate the girl's distance from the scale at Q.
[4 marks]
Define the term 'pressure'.
[2 marks]
State the SI unit of pressure pascal (Pa) , in terms of its base units.
[1 mark]
< ![CDATA[Describe, with the aid of a diagram, how the pressure in a liquid varies with the depth of the liquid.
[3 marks]
State the equation for the pressure difference () between two points in a liquid, which are a vertical distance, , apart.
[1 mark]
Figure 4 shows a U-tube containing two immiscible liquids, X and Y.
If the density of Liquid X is , calculate the pressure (in Pa), due to the liquid column AB, which is 8 cm long.
[3 marks]
Hence, use your answer to (c) (i) to calculate the height, , of the liquid column CD, given that the density of liquid Y is . (State any equations used and fully explain the reasoning in obtaining your answer to (c) (ii).) [Use ]
A young student has just entered secondary school. He was accustomed to having his home-cooked meal warmed up at lunch time in the microwave oven at his primary school. He misses this and suggests to his parents that they buy him a vacuum flask similar to the one shown in Figure 5.
Using the information in Figure 5, explain in terms of the principles of thermal energy transfer how EACH of the following sections of the vacuum flask helps to keep the home-cooked meal warm.
The cork stopper
The vacuum
The double-walled glass vessel with silvered walls
[2 marks]
Determine the mass of the melted ice.
[1 mark]
Calculate the heat lost by the water.
[3 marks]
Write an expression for the TOTAL heat gained by the ice in melting and the melted ice in warming to .
[2 marks]
Hence calculate the specific latent heat of fusion of ice. [Specific heat capacity of water ]
[3 marks]
(a) Draw the electric fields for EACH of the following arrangements. (i) (ii) (iii)
[6 marks]
If the number of electrons transferred from a charged rod to earth through a wire is and the total charge transferred is , calculate
[7 marks]
the magnitude of the charge on one electron
[3 marks]
the current that flows through the wire if it takes for all the electrons to flow to earth.
[3 marks]
State the direction in which the charges will flow, if the rod is positively charged.
[1 mark]
Explain how the static 'build up' of charges on a vehicle could be hazardous.
[2 marks]
Figure 7 shows the experimental arrangement of the apparatus used to carry out the Rutherford's alpha () particle scattering experiment to identify the structure of the atom.
A beam (collimated beam) of alpha particles from a radioactive source was fired at a thin piece of gold foil and the angle of deviation of the alpha particles observed.
Figure 7. Rutherford's alpha particle scattering experiment
[4 marks]
Write the names of the two scientists who assisted Rutherford in performing this experiment.
[2 marks]
Explain why the experiment was carried out in an evacuated chamber.
[2 marks]
State the conclusions that were deduced from EACH of the following observations made from the alpha particle scattering experiment.
[3 marks]
Most of the alpha particles passed through the gold foil undeviated.
[1 mark]
A few alpha particles were deflected from their path but continued through the gold foil.
[1 mark]
A smaller number of alpha particles rebounded.
[1 mark]
Describe the Rutherford model of the atom, based on the conclusions of the experiment stated in (b).
[2 marks]
Energy is produced within stars by the process of fusion where alpha particles help convert beryllium into carbon, according to the equation below.
In the equation above, which symbol is used to represent the alpha particle?
[1 mark]
The following table shows the mass of each nuclei in the process above.
Calculate the energy equivalence of the mass in (d) (ii).
[3 marks]
[5 marks]
[15 marks]
Calculate the loss in mass, , in kg, due to the reaction.
[2 marks]