CSEC Physics Paper 3 May/June 2005 - Free CXC Past Paper with Answers

An investor is interested in a nuclear power station project. He has the option of using natural or artificial radioactive decay processes to obtain energy. In helping him to decide, he consults an engineer who compares the energy obtained from the following TWO nuclear reactions:

natural: $\quad _{83}^{212} Bi \rightarrow _{81}^{208} Tl + _{2}^{4} He + Energy$ artificial: $\quad _{0}^{1} n + _{92}^{235} U \rightarrow _{54}^{A} Xe + _{38}^{90} Sr + 3 \left( _{0}^{1} n \right) + Energy$

Table 1 below gives the data for these nuclides where $u = 1.66 \times 10^{-27} kg$.

Table 1: Showing nuclide and atomic mass

(i) Calculate the number of neutrons in Bismuth (Bi). (3 marks) (ii) Determine the atomic mass number of Xenon (Xe). (2 marks) (iii) Calculate the energy released in EACH nuclear reaction and the ratio of the larger to the smaller. Deduce the recommendation that the engineer will give to the investor. (7 marks)

Calculate the number of neutrons in Bismuth (Bi).

Determine the atomic mass number of Xenon (Xe).

Calculate the energy released in EACH nuclear reaction and the ratio of the larger to the smaller. Deduce the recommendation that the engineer will give to the investor.

Radioactive materials emit alpha ($\alpha$), beta ($\beta$) and gamma ($\gamma$) radiation. Table 2 summarises some of the properties of these types of radiation. Copy the table in your answer booklet and complete the missing entries.

Table 2: Properties of $\alpha$, $\beta$ and $\gamma$ radiation

With the aid of a neat, clearly labelled diagram, describe an experiment to prove the relationship between the angle of incidence, $i$, and the angle of reflection, $r$, for a ray of light incident on a plane mirror.

Figure 2 is a side view of ABCD, a prism made from fused quartz (a type of glass) of refractive index 1.46.

Figure 2

The ray MN is incident on face AD as shown.

(i) Show that MN will be totally internally reflected from the face AB. (7 marks) Redraw the diagram in your answer book. (ii) Determine, $\theta_m$, the angle which the reflected ray makes with the face BC at point P. (iii) Sketch on your diagram the ray from point P, showing clearly the path from P through to its emergence from the prism.

Indicate any refraction. (5 marks)

Show that MN will be totally internally reflected from the face AB. Redraw the diagram in your answer book.

Determine, $\theta_m$, the angle which the reflected ray makes with the face BC at point P.

Sketch on your diagram the ray from point P, showing clearly the path from P through to its emergence from the prism.

Indicate any refraction.

With the aid of a labelled diagram describe an experiment to determine the centre of gravity of an irregularly shaped sheet of cardboard.

Figure 3 shows a bicycle of mass $15 kg$ resting in a vertical position, with the front and back wheels touching the horizontal ground at points P and Q respectively, where PQ = $1 m$. The centre of gravity of the bicycle is vertically above O, a point on PQ where PO = $30 cm$.

Figure 3

Given that the normal reactions of the ground on the front and rear wheels are $R_1$ and $R_2$ respectively, write TWO equations, in $R_1$ and $R_2$, which satisfy the conditions of equilibrium.

Kenny and Candy decided to sit on a see-saw while visiting a local play park. Candy, of mass $50 kg$, sat $250 cm$ from the pivot of the seesaw.

(i) Where should Kenny, of $60 kg$ mass, sit so that a state of stable equilibrium exists? (5 marks) (ii) What should Kenny do if he wanted to elevate Candy? (3 marks)

(Acceleration due to gravity = $10 N kg^{-1}$)

Where should Kenny, of $60 kg$ mass, sit so that a state of stable equilibrium exists?

What should Kenny do if he wanted to elevate Candy? (Acceleration due to gravity = $10 \text{ N kg}^{-1}$)

Distinguish between EACH of the following pairs of terms:

'Condensation' and 'vaporisation'

Describe FULLY the process of sublimation.

For the changes of state mentioned in a) and b) above to take place energy must be added to or removed from a substance. Give the general name for this type of energy and state what happens to the temperature during these processes.

A student placed 700 g of water at $28^\circ\text{C}$ in a freezer. After 6 minutes and 15 seconds the water was transformed to ice. Calculate (i) the heat energy transferred from the water during the temperature change

the latent heat of solidification, given that $235200 \text{ J}$ of heat energy was transferred during the change of state

the rate of heat energy transfer for the entire process. (Specific heat capacity of water = $4200 \text{ J kg}^{-1}\text{K}^{-1}$)