cameroon gce advanced level 2025 engineering science 2

SECTION A

Question 1:

• A cell with an electromotive force (e.m.f) of 1.5 V and internal resistance $3\Omega$ is connected in series with a cell of e.m.f 2.0 V and internal resistance r.
• A resistor with a constant resistance of $10\Omega$ is connected across the ends.
• A current of 0.25 A is produced.
• Task: Determine the value of r.

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Question 2:

• Compare images formed by a converging lens and a diverging lens, both with a focal length of 20 cm.
• The object is placed 22 cm from the lens in each case.

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Question 3:

• A homologous series of an organic compound is represented by the general formula Cn​H2n+1​OH.
• Task: Write down the formula of the third member of this series and draw diagrams showing the structural formulae of the isomers.

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Question 4:

• The energy released by the Sun is the result of a thermonuclear fusion in its core, where protons are fused together into helium nuclei through a complicated process.
• The overall reaction is represented by the following equation:

  411​H→24​He+other particles + energy

• The mass of the “other particles” is negligible.
• Data:
  • mass of proton = $1.00728u$
  • mass of helium nucleus = $4.00150u$
  • 1u=1.66×10−27kg
• Task (a): Explain why the process of forming helium nuclei from protons is difficult to achieve on Earth.
• Task (b): Calculate the energy released by the sun for every kilogram of protons fused to form helium nuclei.

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Question 5:

• Task: Distinguish between empirical formula and molecular formula.

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Question 6:

• Task: List the factors that affect the magnitude of the torque for current flowing through a conducting loop.

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Question 7:

• Figure 1 shows an incompressible fluid with a density of 1.0×103kgm−3 flowing through a horizontal pipe.
• The area of the pipe increases from 2.0cm2 at point D to 5.0cm2 at point H.
• The velocity at point D is 20ms−1.
• Task (a): Write down the continuity equation given that the velocities at D and H are VD​ and VH​ while the cross-sectional areas are AD​ and AH​ respectively.
• Task (b): Calculate the pressure difference between the points D and H.