WARI SECONDARY SCHOOL FORM SIX PRE NATIONAL PHYSICS 3A




Question 1: Simple Harmonic Motion (SHM) with a Meter Rule

This question investigates simple harmonic motion using a meter rule suspended by threads.  

  • Objective: To determine the relationship between the period of oscillation of a suspended meter rule and the distance between the suspension points, and to calculate the acceleration due to gravity (g).

Procedure:

  • Students set up the apparatus as shown in the diagram, adjusting the length of the threads (L) and the distance between them (d). 

  • They make the ruler swing and measure the time for a number of oscillations to find the period (T).  

  • They repeat this process for different values of 'd'.  

Measurements and Analysis:

  • Students record their measurements in a table, including values of d, t, T, and 1/d.  

  • They plot a graph of T against 1/d.  

  • They use the graph and a given formula to calculate the value of 'g'.  

Physics Concepts: This question assesses understanding of:

  • Simple harmonic motion.

  • Period and frequency of oscillations.

  • Factors affecting the period of a physical pendulum.

  • Graphical analysis of data.

  • Calculation of acceleration due to gravity.

Question 2: Cooling Curve



This question examines the rate of cooling of a calorimeter under different conditions.  

  • Objective: To investigate how the surface properties of a calorimeter affect its rate of cooling.

Procedure:

  • Students blacken the outer surface of a calorimeter and fill it with hot water, recording the temperature as it cools.  

  • They then repeat the experiment with the calorimeter covered in metal foil.  

Measurements and Analysis:

  • Students draw a diagram of the experimental setup.  

  • They record their temperature and time measurements in tables.  

  • They plot cooling curves for both the blackened and foiled calorimeter on the same axes.  

  • They determine the time taken for the water to cool from 80°C to 75°C for each case and compare the results.  

Physics Concepts: This question assesses understanding of:

  • Heat transfer, specifically cooling.

  • The effect of surface properties (black vs. reflective) on heat radiation.

  • Experimental technique in calorimetry.

  • Graphical representation and interpretation of cooling curves.


Question 3: Resistance of a Material



This question focuses on determining the resistance of a material (aluminum foil) using a meter bridge.  

Context: The question is framed within the context of electroplating in a car manufacturing industry.  

Objective: To measure the resistance of an aluminum foil sample and then estimate the resistance of a larger sheet of the same material.

Procedure:

  • Students set up a meter bridge circuit with the aluminum foil and a standard resistor connected in parallel.  

  • They vary the resistance in a resistance box and find the balancing length on the meter bridge for each resistance value.  

Measurements and Analysis:

  • Students draw a circuit diagram of their setup.  

  • They tabulate their results, including the reciprocal of the balancing length (1/L).  

  • They derive the equation governing the experiment (based on the meter bridge principle and parallel resistances).  

  • They plot a graph of 1/L against the resistance.  

  • They determine the gradient of the graph.  

  • They use the gradient and other information to estimate the resistance of a larger aluminum sheet.  


Physics Concepts: This question assesses understanding of:

  • Electrical circuits.

  • Resistance and resistivity.

  • The meter bridge principle.

  • Resistors in parallel.

  • Data analysis and graph interpretation to determine resistance




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