PHYSICS PAPER 3 - KCSE 2019 MOKASA PRE MOCK EXAMINATION

Question 1
You are provided with the following apparatus

• One test tube
• One 10ml measuring cylinder
• A piece of string
• A ½ metre rule and electronic beam balance.
• One retort stand
• One boss and a clamp
• A plasticine
  1. Proceed with the experiment as follows
     1. Record the mass ‘m’ of the test tube indicated on the side by a sticker label
        M=……………………………………………………………………g                              (1/2mark)
     2. Clamp the boiling tube vertically with its base resting on a flat surface. Pour 2cm³ of water from the measuring cylinder into the boiling tube.
        
        Record the volume, V, and the length ‘L’ of the water column in the test tube in the table below. Repeat with values of V=2cm^3, 4 , 6, 8, 10, and 12cm³    (4marks)
        

        Volume V (cm3)	Length     L (cm)
        2
        4
        6
        8
        10
        12

  2.  
     1. Plot a graph of volume V against Length ‘L’ of water column.         (4marks)                                                                                           
     2. Determine the slope ‘S’ of the graph and state its units.                          (2marks)
     3. Measure the length L_o, of the test tube
     4. Wind the cotton thread round the test tube. The turns should touch one another but must not overlap.
     5. Unwind the cotton thread of N turns and measure its length
     6. Calculate the quantity V of the glass material of which the test tube is made using the formula   (2marks)
        
  3. Roll the plasticine to form a spherical ball that can freely enter the test- tube measure its mass and record.
     M_o=…………………………………………………g
     M_o=…………………………………………………Kg             (1mark)
  4. Empty the test tube and put of water from the measuring cylinder into the test tube. Measure and record the length , L_2.
     L₂₌………………………………………………………… cm               (1/2marks)
  5. Carefully slide the ball into the test tube and record the new length, L₃
     L₃=…………………………………………………………………….cm (1/2cm)
  6. From the graph determine the volume V₁ and V₂ corresponding to L₂ and L₃
     V₁₌....................................................................................... cm³    
     V₂=…………………………………………………………………… cm³           (1mark)
  7. Determine the density, of the plasticine ball given that (2marks).   
             

Question 2
You are provided with the following apparatus:

• Resistor wire mounted on a mm scale, labeled AB.
• Voltmeter
• Ammeter
• Two new dry cells and a cell holder.
• Switch.
• Seven connecting wires.
• A jockey
  
  
• Procedure
  1. Set up the circuit as shown below.
     
  2. Remove the crocodile clip from the resistance wire AB and close the switch. Record the voltmeter reading.
     E=………………………………V                                                                (1mark)
  3. Attach the crodile clip to the resistance wire such that L= 10cm. Record the voltmeter and ammeter readings in the table below.
  4. Repeat the procedures in (c) above for the other values of L as indicated in the table below and complete the table.
     

     Length L, (cm)	80	50	30	20	10
     Current I,(A)
     P.d V(V)
     E-V (V)
     v E-V
     V=R (Ω) I

  5. Plot the graph of V/(Y-V)(Y-axis) against R.                                                      (5 marks)                                                                                                             
  6. Determine the slope S, of the graph.                                                           (3mark)
  7. The graph is given by the equation5K=5v/(E-V)-mR:    
     determine the values of:
     1. m
     2. K                                                                                                 (1mark)