You are provided with the following

• Candle wax
• Bunsen burner
• Stop watch
• A boiling tube
• A thermometer range -100C – to 1100C.
• A cork with a hole in the centre.
• A complete retort stand
• A tripod stand with wire gauge
• Some hot water in a beaker.

Proceed as follows
a) Heat the water in the beaker until it starts to boil. Place some candle wax in a boiling tube and heat the wax in water bath as shown in figure below

b) When the wax has completely melted, continue heating and insert the thermometer in the boiling tube through the hole in the cork.

c) Continue heating until the thermometer record a maximum temperature. Read and record this temperature as T0 (1 mark) T0=....................................................................... 0C

d) Remove the boiling tube from the boiling water and simultaneously start the stop watch. Record the temperature of the cooling wax at intervals of three minutes in the table below.

e) Plot the graph of temperature (y-axis) against time t. (5mks)

f) From the graph determine.

i) The rate of cooling at time t=7min. (4mks)

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ii) The temperature of wax after 10 minutes. (2mks)

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g) During heating, there was no further change in temperature at T0. Explain (1mk)

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You are provided with the following:

• Two new dry cells.
• Cell holder
• Bulb
• Bulb holder
• Nichrome wire labelled AB
• A milliameter (0 -1A)
• Voltmeter
• Jockey
• Five connecting wires, four with crocodile clips.

Set up your circuit as shown in figure below.

The crocodile clip connecting the cell can act as the switch.

Proceed as follows

i) Place the jockey on the Nichrome wire so that the length L is 10cm. Record the reading on the voltmeter and the ammeter in the table below.

ii) Repeat procedure (i) for the other values of L given in the table shown below.

iii) Plot a graph of current, I (y-axis) against voltage. (5mks)

iv) Determine the slope of your graph when current flowing is 0.15mA (3mks)

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Part B (5marks)

You are provided with the following:

• A glass block
• Soft board
• Five(5) optical pins
• Four (4) thumb tacks
• White piece of paper
• Half metre rule

Proceed as follows
i) Using the half metre rule measure the width, W of the glass block.

W=...............................................................................cm (1mk)

ii) Place the glass block on the plain piece of paper. Draw its outline

iii) Remove the glass block. Mark a point X one of the longest sides of the outline around the mid-way point. Push a pin P1 on this point.

iv) Replace the glass block to sit perfectly on its outline.

v) On the opposite side push two pins P2 and P3 on the right side of X so that they appear to be in line with P1

vi) Repeat step (v) but with two other pins P4 and P5 on the of X vii) Remove the glass block and the pins. Draw a line joining P2 and P3 then another joining the position P4 and P5. Extend the lines P2 and P4 P5 to intersect at Y as shown in fig. 2

viii) Measure the distance XY (2mks)

XY.....................................................................

ix) Calculate the value given that;