Physics Paper 1 Questions and Answers - Lainaku 1 Joint PreMock Exams 2023

• Answer all the questions in sections A and B in the spaces provided.
• All workings must be clearly shown.
• Mathematical tables and non-programmable silent electronic calculators may be used.
• Candidates should answer the questions in English

                                                                                   SECTION A (25 MARKS)

1. State the procedure followed when using a metre rule               (3mks)
2. Define a compression force.              (1mk)
3. Mosquito larvae floats on water surface. Explain how oiling controls the breeding of mosquitoes.   (1mk)                                     
4. Complete the table below          (3mks)
   
   

   Equilibrium state	Effect of external force on position of centre of gravity
   Stable
   Unstable
   Neutral

5. A model toy boat of cross-sectional area 1000 cm² floats in fresh water. If the boat sinks 6cm as a result of loading, calculate the load on the boat. Given that the density of water is 1g/cm³      (3mks)                                                                                                               
6. The type of the material is one factor which affects spring constant. State other two factors.           (2mks)                                         
7. Water with negligible viscosity flows steadily through a horizontal pipe of varying cross-sectional area. At a point A of area 10cm², the velocity is 0.2m/s. Calculate the pressure difference between A and B. If the area at B is 2.5cm² and density of water is 1000kg/m³.                (3mks)   
8. State the principle of moments.                (1mk)
9. Draw a sketch of displacement time graph for a body moving with decreasing velocity.         (2mks)
10. Define the term velocity ratio as used in machines.     (1mk)
11. The diagram below shows a block being dragged on a horizontal floor. If the coefficient of kinetic friction is 0.40, determine force F required to move the box at uniform speed.        (3mks)
                                                         
12. State the part of the vacuum flask which minimizes heat loss by                   (2mks)
    1. Radiation
    2. Conduction

                                                                                        SECTION B (55 MARKS)

13.  
    1. Define pressure and state its SI unit           (2mks)
    2. Show that the pressure exerted by a fluid is given by the formula. P = hρg. Where h is the height of the fluid, ρ is the density of the fluid and g is the acceleration due to gravity.    (3mks)
    3. The figure below shows a U-tube manometer containing air, mercury and water.  Calculate the pressure exerted on the trapped air.  (Take atmospheric pressure to be 1.05 x 105 pa, density of mercury and water to be 13600kg/m³ and 1000kg/m³ respectively).          (3mks)
                                                           
    4. Explain why a girl wearing high heeled shoes makes deeper marks while walking on a soft ground than when wearing toughees shoes.               (2mks)
    5. The barometric height at the base of a mountain is 70cmHg. If the mountain is 435.2m high, determine the reading of the mercury barometer at the top of the mountain. Take density of mercury as 13600kg/m³ and that of air as 1.25kg/m³.                         (3mks)
14.  
    1. State Pressure Law (1mk)
    2. The following diagram shows a set-up of apparatus used to verify Charles Law.
                                               
       1. Give the name of part labelled X          (1mk)
       2. State the component of X          (1mk)
       3. State two functions of the part named in (i) above?    (2mks)
       4. Briefly explain how the set up above is used to verify Charles Law  (3mks)
    3. A certain mass of hydrogen gas occupies a volume of 1.6m³ at a pressure of 1.5 x 10⁵Pa and a temperature of 12°c. Determine the volume when the temperature is 0°C at a pressure of 1.0 x 10³Pa.          (2mks)
15.  
    1. Define the term angular velocity.                        (1mk)
    2. The diagram below show a stone of mass 500g moving in a vertical circular path of radius 50cm centre O. It is whirled with a frequency of 2 cycles per second.
                                                                      
       1. Calculate
          1. Its linear velocity      (2mks)
          2. Tension at A.            (3mks)
          3. Tension at B.           (2mks)
          4. Tension at C.           (3mks)
       2. At what point is the string likely to break?      (1mk)
       3. Indicate the direction of centripetal force on the diagram.       (1mk)   
16.  
    1. Define the term specific heat capacity.    (1mk)
    2. State two precautions to be taken when carrying out the experiment to determine specific heat capacity of solid by electrical method.                  (2mks)
    3. A copper calorimeter of mass 0.12kg contains 0.1kg of kerosene at 15°C. If 56g of aluminium at 80°C is transferred into the liquid and the final temperature of the mixture is 27°C. (Taking heat loss to be negligible, specific heat capacity of aluminium is 900J/kgK and copper 400J/kgK). Determine:     
       1. Heat absorbed by kerosene and calorimeter.        (3mks)                                             
       2. Heat lost by aluminium      (2mks)
       3. The specific heat capacity of kerosene.    (2mks)   
17.  
    1.  
       1. Define the term diffusion       (1mk)
       2. State two factors affecting the rate of diffusion in gases.     (2mks)
       3. Compare liquids and gases in terms of intermolecular forces                                (1mk)
    2.  
       1. The diagram below shows a bimetallic strip at room temperature. Draw the strip when temperatures are lowered below room temperature. Given that B has a higher linear expansivity than A.    (1mk)
                                                         
       2. Explain your answer in b(i) above.        (1mk)
       3. The diagram below shows two glass tumblers filled with boiling water at the same time. State and explain the observation.                  (3mks)
                                                 
          
          

                                                                         MARKING SCHEME

                                                                                               SECTION A

1	i.   Place the metre rule in contact with the object  ii.  Place the end of the object against the zero mark on the scale  iii. Position your eye perpendicularly above the scale	3mrks
2	A force acting towards an object leading its decrease in size	1mrk
3	Oil is an impurity, it lowers the surface tension of water and the larvae sinks	1mrk
4	Equilibrium state   Effect of external force on position of centre of gravity   Stable   Raised    Unstable   Lowered    Neutral   Unchanged
5	U = vρg;               = 1000 x 10-6 x 6 x 1000 x 10;               = 60N;	3mrks
6	The diameter of the spring Number of turns per unit length Length of the spring               (any two)	2mrks
7	A1V1 = A2V2                       10 x 0.2 = 2.5 V2                          V2 = 0.8 m/s;                            P = ½ (V1-V2)ρ;                               = ½ (0.8 – 0.2) x 1000                               = 300 Pa;	3mrks
8	Sum of clockwise moments is equal to sum of anticlockwise moments about the same point	1mrk
9
10	The ratio of effort distance to load distance	1mrk
11	F = µR;                                  = 0.4 x 50 x 10;                                  = 200N;	3mrk
12	(i).  Double silverly walls   (ii). Double glass walls/plastic lid/ rubber pads/plastic casing	1mk   1mk
	SECTION B
13	Force acting perpendicularly per unit area. SI Unit is pascals/newton per square metre Pressure = F/A Volume = Ah     Mass = Ahρ   Weight = Ahρg; Pressure = Ahρg/A;                                   = hρg; P1 = P2 Pair = Pwater + Pmercury + Patmospheric;        = 105000 +0.25 x 1000 x 10 + 0.10 x 13600 x 10;        = 121100N/m2; High heeled shoes exerts greater pressure compared to the flat shoes. The smaller the area of contact the higher the pressure exerted P = hρg; X x 13600 x 10 = 435.2 x 1.25 x 10                     X  = 0.04m ; = 4cm                           Reading = 66cmHg;	2mks         3mks        3mks      2mrks             3mks
14	Pressure of a fixed mass of a gas is directly proportional to the absolute temperature provided volume is kept constant.   Index Sulphuric acid Acts as a pointer Acts as a drying agent   Stir the bath as you continue to heat; Take and record the readings of temperatures and corresponding readings of volumes(height); Plot the graph of volume against absolute temperature; The graph is a straight line passing through the origin.                                   P1V1 = P2V2;                        T1         T2         150000 x 1.6 =  1000 x V2                   295                273                                               V2 = 222.1cm3;	1mk     1mk   1mk       2mks           3mks        2mks
15	a. It is the rate of change of angular displacement with time  b. (i) (I) V = 2πrf;                  = 2 x 22/7 x 0.5 x 2 = 6.2857m/s;         (II) TA = MV2 – mg;     T = 0.5 x 6.2857 x 6.2857 – 0.5 x 10; = 34.51N;                         r                                             0.5         (III) TB =  MV2 ;                               r                      = 0.5 x 6.2857 x 6.2857                                     0.5                     = 39.51N;         (IV)  TC = MV2 + mg;                             r                     = 0.5 x 6.2857 x 6.2857 + 0.5 x 10;                                         0.5                    = 44.51N;     (ii)  C     (iii)	1mk   2mks     3mks                 2mks               3mks           1mk         1mk
16	Quantity of heat required to raise the temperature of a substance by 1K or 1°C Fill all the holes with oil Highly lagging and polishing of the metallic block  Q = mc∆Ɵ ;      = (0.12 x 400 x 12) + (0.1 x c x 12);      = 576 + 1.2c  J; Q = mc∆Ɵ;     = 0.056 x 900 x 65     = 3276J; Heat lost = heat gained     576 + 1.2c = 3276;                     c = 2250J/kgK;	1mk    2mks     3mks        2mks    2mks
17	The movement of molecules from a region of high concentration to a region of low concentration.   Density of gases Size of the molecules   Diffusion gradient      (any 2) The intermolecular forces between solids is stronger than that in liquids   B having a higher linear expansivity it contracts more than A; A is likely to crack but B will not; The thin glass wall expands uniformly; but the thick glass wall has non-uniform expansion leading to its cracking;	1mk                    2mks        1mk      1mk      1mk   3mks