cxc jan 2000 p2

TEST CODE 002492 January 2000

FORM TP 97110

CARIBBEAN EXAMINATIONS COUNCIL SECONDARY EDUCATION CERTIFICATE EXAMINATION PHYSICS Paper 02 - General Proficiency 1 ½ hours

READ THE FOLLOWING DIRECTIONS CAREFULLY 1 You MUST use this answer booklet when responding to the questions. For each question, write your answer in the space provided and return the answer booklet at the end of the examination. 2. ALL WORKING MUST BE SHOWN in this booklet since marks will be awarded for correct steps in calculations. 3.

Attempt ALL questions.

4.

The use of non-programmable calculators is allowed.

5.

Mathematical tables are provided.

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO Copyright © 1999 Caribbean Examinations Council. All rights reserved. 002492/January 2000

CXC January 2000 P 2 Q 1 DATA ANALYSIS about 30 minutes In this question you are to find the value of the acceleration due to gravity on the Moon, gm and use your value in calculations. (a) You are given a graph of distance, d, against time, t, for an object falling from rest on the Moon. From the graph, obtain six pairs of values of d and t. Tabulate these below along with the corresponding values of t2. [9] 18

16

14

12

10 m / d 8

6

4

2

0 0.0

1.0

2.0

3.0

4.0

5.0

t/s

(b)

Use these values to plot a graph of d against t2 on another graph page

(c) Find the slope, S, of the graph you have plotted.

[9]. [4]

(d)

Given that S = gm /2, find the value of gm.

[2]

(e)

Use the graph given above to find the average speed during the first four seconds.

[4]

(f) Using the average speed calculated in part (e) above, or otherwise, find the speed of the object after it has fallen for 4 seconds. [3]

Total 30 marks

(a)

CXC Jan 2000 P 2 Q 2 Explain what is meant by the 'dispersion' of light

[1]

(b) (i) A narrow beam of white light strikes one of two identical glass prisms as shown in Figure 1. Complete the diagram to show the path taken by the white light. Indicate where the red and blue light strike the principal axis. [4] (ii)

Monochromatic blue light strikes the other prism as shown. Complete the path of the blue light [3]

(iii) The refractive index of glass for blue light is 1.55 and that of red light 1.51. Which colour light travels more slowly in glass?

[1]

(iv)

Find the wavelength of red light in glass if its wavelength in air is 6.5 x 10-7 m..

[3]

(v)

Calculate the frequency of red light in air and its frequency in glass.

[4]

(speed of red light in air = 3.0 x 108 m s-1.)

Total 16 marks

CXC Jan 2000 P 2 Q 3 (a) (i) A 3 V source of e.m.f. consists of two identical 1.5 V dry cells. Draw the symbol for this source. [2] (ii) The source is in a series circuit with a switch, an ammeter, a semiconductor diode and a 120 Ω resistor. The diode is placed so that it has zero effective resistance. Draw a circuit diagram, indicating the direction of current flow when the switch is closed and the polarity of the ammeter. [4] (iii)

(b)

Calculate the magnitude of the current. [3]

(i)

Identify the logic gate symbols by completing the table. [2]

(ii)

Complete the truth tables for the following logic gates. [4]

NAND INPUTS OUTPUT A B Z 0 0 0 1 1 0 1 1

OR INPUTS A B 0 0 0 1 1 0 1 1

OUTPUT Z

(a)

CXC Jan 2000 P 2 Q 4 What is meant by the 'upper' and 'lower fixed points' of the Celsius temperature scale?

[2]

(b) Figure 2 shows the position of the meniscus in a mercury thermometer at 0 0C, at 100 0C and at an unknown temperature, X. (i) Use the information in the diagrams to find the temperature, X.

[4] (ii)

What would be the value of X on the Kelvin scale of temperature? [2]

(iii)

If the temperature of a body changes by 400 C, what would the temperature change be in kelvin ? [1]

(c) (i) Water is heated at the top of a test-tube as shown in Figure 3 . State what would he observed and explain these observations. [3]

(ii) In a refrigerator, the cooling element is at the top. Explain how the cooling element is able to cool all the contents of the refrigerator.

[3]

Total 15 marks

CXC Jan 2000 P 2 Q 5 A motorist, travelling in a car at a constant speed of 30 m s-l on a local highway, overtakes a policeman on a motorcycle travelling at 20 m s-l . The policeman immediately gives chase and the motion of the vehicles, for the next 10 seconds, is represented on the velocity time graph (a) term 'constant speed'.

(b)

(c)

(d)

Explain the meaning of the [1]

In terms of the forces acting, explain how the car maintains a constant speed

[2]

From the graph calculate the: (i)

Acceleration of the motorcycle

[3]

(ii)

Distance travelled by the car in the 10 seconds

[2]

(iii)

Distance travelled by the motorcycle in the 10 seconds

[3]

Comment on your answers to (c) (ii) and (c) (iii) above.

[1]

(e) The motorist is arrested by the policeman for exceeding the 100 km h-1 speed limit. He says he is innocent since he had only been driving for 10 minutes and therefore could not have travelled 100 km. Explain the motorist's misunderstanding. [2]

Total 14 marks.