APPLIED PHYSICS NATIONAL EXAM L5 TSS 2022-2023

Here are the questions and answers for the Applied Physics exam (T209)


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SECTION A: Attempt all questions (55 marks)

1. a) An electric charge located at point P(1, 15°, 5) is said to be in which coordinate system?

(i) Cartesian system
(ii) Cylindrical system
(iii) Spherical system
(iv) Space system

Answer: (iii) Spherical system

1. b) Give the difference between a systematic error and a random error.

Systematic error: consistent error caused by faulty instruments or incorrect calibration.

Random error: Unpredictable error due to variations in measurement or environmental factors.



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2. A teacher used equipment to demonstrate the motor effect. Increasing the current can increase the force acting on the copper rod. Give three other ways to increase the force.

Answer:

1. Increase the magnetic field strength.
2. Increase the length of the conductor in the field.
3. Improve conductivity or use a stronger material.

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3. a) State three natural causes of a landslide.

Answer:

1. Heavy rainfall
2. Earthquakes
3. Volcanic eruptions


3. b) Use physics concepts to explain why a landslide occurs.

Answer 

: Landslides occur when the force of gravity acting on soil or rocks overcomes friction and cohesion due to external factors like water infiltration or seismic activity.


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4. a) What is the difference between a longitudinal wave and a transverse wave?

Answer:

Longitudinal wave: Particles vibrate parallel to wave direction (e.g., sound waves).

Transverse wave: Particles vibrate perpendicular to wave direction (e.g., light waves).


4. b) What are the conditions to obtain clear interference?

Answer:

1. Coherent sources (same frequency & phase).
2. Same polarization.
3. Equal or nearly equal amplitude.

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5. a) What is the meaning of FM?

Answer: FM stands for Frequency Modulation.
 
5. b) Define the following terms used in communication.

i) Amplitude-modulated carrier wave: A wave whose amplitude varies with the input signal (used in AM radio).

ii) Cellular Network: A network of interconnected base stations enabling mobile communication.


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6. Define the following terms related to optical fiber communication.

a) Acceptance angle: The maximum angle for light to enter a fiber and undergo total internal reflection.
b) V-number: A parameter determining mode behavior in optical fibers.


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7. Give expressions for velocity and displacement in uniformly accelerated motion.

Answer:

Velocity
Displacement

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8. a) State the causes of earthquakes.

Answer:

1. Tectonic plate movement
2. Volcanic activity
3. Human activities (e.g., mining, reservoir-induced seismicity)



8. b) Define a cyclone and explain whether Figure 2 is a cyclone in the Southern or Northern Hemisphere.

Answer:

Cyclone: A low-pressure system with strong rotating winds.

If the cyclone rotates clockwise, it’s in the Southern Hemisphere. If it rotates counterclockwise, it’s in the Northern Hemisphere.

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9. Consider two parallel current-carrying wires. Draw the direction of the magnetic fields and forces.

Answer:

Magnetic fields follow the Right-Hand Rule.

If currents flow in the same direction, the force is attractive.

If currents flow opposite, the force is repulsive.

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10. a) Give any three greenhouse gases.

Answer:

1. Carbon dioxide (CO₂)
2. Methane (CH₄)
3. Water vapor (H₂O)


10. b) Explain how greenhouse gases affect climate change.

Answer: Greenhouse gases trap heat radiation, causing global warming and climate change.


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11. An object is placed in front of a converging lens at a distance between F and 2F. Draw and describe the image.

Answer:

The image is real, inverted, and magnified.



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12. a) State Ohm’s law.

Answer: 

12. b) Calculate the current in a circuit with a 2V EMF, 0.94Ω internal resistance, and 22Ω external resistance.

Answer:
.


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13. Calculate the gas tank pressure if atmospheric pressure is 100 kPa and mercury height is 10 cm.

Answer:


 Pa


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14. a) State Coulomb’s law.

Answer: 


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15. a) State two renewable energy sources.

Answer:

1. Solar energy


2. Wind energy



15. b) How many wind turbines of 0.6 MW are needed to replace a 1500 MW coal plant?

Answer:
 turbines.


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SECTION B: Attempt any 3 questions (30 marks)

16. a) If a bicycle and a lorry collide and stick together, what type of collision is this?

Answer: Inelastic collision (momentum conserved, kinetic energy not).


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17. Calculate velocity and acceleration components of a rotating rod at 45°.

(Use kinematics formulas for angular motion).


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18. a) What is negative feedback in operational amplifiers?

Answer: Feedback that stabilizes gain and improves performance.


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SECTION C: Attempt 1 question (15 marks)

21. a) Name and describe Carnot cycle processes 1-2 and 4-1.

Answer:

1-2: Isothermal Expansion ()

4-1: Isothermal Compression


21. c) Calculate heat transfer and power output in a gas turbine.

Answer:

Heat transfer: 

Power output: 



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