Get the Answers here Form 4 End Term 1 Exams 2023 Questions and Answers

Question one

You are provided with the following:

• 2 new dry cells size D
• A cell holder
• A switch
• A millimeter of range 0 to 1 mA
• A capacitor labeled C
• 8 connecting wires; at least four with crocodile clips on one end
• A stopwatch
• A carbon resistor labeled R

Proceed as follows

Connect the circuit as shown in the figure 1below, where P and Q are crocodile clips.

mA

R

Crocodile clips

P

Q

C

S

1. Close the switch S
2. Name the process which takes place when the switch S is closed

                     ……………………………………………………………….          (1 mark)

• Connect the crocodile clips P and Q. Observe and record the highest reading of the millimeter I_o

                      ……………………………………………………………….              (1 mark)

• Open the switch S and at the same time start the stopwatch to measure the time taken for the current to decrease to four fifth the value of I_o i.e. ⁴/₅I_o. Record your value in the table 1.
• Close the switch S for a second time and observe the deflection in the millimeter. (the pointer should rise back to the same initial value I_o)
• Repeat part (b) for other values of current as shown in the table 1 below.   (8 marks)

Current I(mA)	4/5Io	3/4  Io	2/3 Io	1/2 Io	2/5 Io	1/3 Io	1/4 Io
Your calculated fraction of Io(mA)
Time t(s)

•  Plot a graph of Current I (y – axis)(mA) against time t(s)                            (5 marks)
• From your graph, findW the value of I when t = 10s.                       (2 marks)

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1. Given that A = 10W, determine the value of A.                                            (2 marks)

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• Determine the voltage across R att = 10sgiven that R = 4.7kΩ                     (1 mark)

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Question Two

You are provided with the following;

• a rectangular glass block
• 4 optical pins
• 2 thumb pins
• a soft board
• a plain paper

Proceed as follows: Place the glass block on the plain paper with one of the largest face upper most.  Trace round the glass block using a pencil as shown below. 

 

(b)       Remove the glass block and construct a normal at B.  Construct an incident ray AB of angle of incidence, i = 20⁰.

(c)         Measure the breadth b of the glass block                                                   (1 mark)

 

                        ……………………………………………………………

(c)       Replace the glass block and trace the ray ABCD using the optical pins.

(d)       Remove the glass block and draw the path of the ray ABCD using a pencil. 

(e)        Measure the length L and record it in the table below

                                                                                                                                    (6 marks)

(f)        Repeat the procedure above for the angles of incidence given. 

 

 

 

(g)       Calculate the values of  and Sin² I; and record in the table above.

 

 

 

 

 

 

 

 

 

 

(h)       Plot a graph of  (y-axis) against Sin²i.                                                       (5 marks)

 

 

 (i)       Calculate the gradient S of the graph                                                          (3 marks)

 

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Given that the equation of that graph is; 

 

(j)        Determine the value of n                                                                              (3 marks)

 

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(k) Present your work sheet; attached to the exam paper                                              (2 mark)