# Mock exam paper C Higher Level Marking Scheme

Pre-Leaving certificate Examination 2013

Physics- Ordinary level

W: http://www.irevise.com/ T: 091 - 520400

Section A (120 marks)

Answer three questions from this section.

Each question carries 40 marks.

1. In an experiment to verify the principle of conservation of momentum the student reported the following:

I set up the necessary apparatus. I measured the masses of the two trolleys . I measured the distance travelled and the time to travel this distance and hence calculated the velocities of the trolleys. Using that data I verified the law of conservation of momentum

(i) draw a labelled diagram of the apparatus used (12)

Labelled diagram with Trolleys, airtrack, method to join trolleys, method to measure time (4x3)

(ii) describe how the student measured time in the experiment (6)

Ticker tape or light gates described (6)

(iii) How did the student calculate the velocity of the trolleys (9)

Measure distance travelled in 10 spaces, each space = 1/50 s , vel = dist/time (3x3)

(iv)How did the student calculate the momentum of the trolleys? (6)

Momentum = mass x velocity (6)

(V) how did the student verify the law of conservation of momentum? (7)

Momentum before calculated, momentum after calculated , should equal each other (7)

1. The student performed an experiment to measure the focal length of a concave mirror. The following table of results were obtained
 Object distance from mirror (u) /cm Image distance from mirror (v) /cm 29 64 37 43 40 41 50 35 55 33 60 30

Draw a diagram of the apparatus used in the experiment (9)

Labelled diagram with u, v, correct shaped mirror (3x3)

Plot a graph of 1/u against 1/v , putting 1/v on the vertical axis (16)

Table of data (4)

Labelled axes (3)

Suitable scale (3)

Points plotted correctly (6)

What does the graph tell you about the relationship between 1/u and 1/v (8)

Proportional – straight line through origin ...