Physics Questions and Answers - Form 2 Term 1 Opener Exams 2021

1. Express each of the following volumes in SI unit giving your answer in standard form(2marks)
   1. 25000cm³
   2. 0.5675cm³
2. State the law of magnetism. (1mark)
3. The figure shows an electromagnet. State the polarities at X and Y.(2 marks)
   
4. Dust particles in air appear to move randomly, explain this observation.(1 marks)
5. The diagram below shows a section of a micrometer screw gauge.
             
   
   1. State the smallest measurement that can be made by the measurement that can be made by the micrometer screw gauge. (1 mark)
   2. What is the correct reading of the micrometer screw gauge if it has an error of 0.25cm (3 marks)
6. State two properties of magnetic field lines(2marks)
7. A charge of 180coloumbs flows though a lamp every minute. Calculate the current flowing through the lamp(3marks)
8. The figure below shows part of a vernier caliper when the jaws are closed without an object between the jaws.
            
   
   1. What is the value of the zero error of the calipers?(1mark)
   2. A student used the same vernier calipers in (a) above to measure the diameter of a test tube whose actual diameter is 2.15cm. What was the reading shown by the calipers(3marks)
9. Explain why repulsion is the sure test for polarity of a magnet(1mark)
10. Explain why a gold leaf is electroscope casing is made up of metal(1mark)
11. Use domain theory to explain the difference between magnetic and non magnetic materials (2marks)
12. On the graph provided, sketch a graph of density against Temperature of a given mass of water(2 marks)
    
13. State two properties of a good thermometric fluid(2marks)
14. State one application of magnets.(1mark)
15. State the laws of reflection (2mks)

Marking Scheme

1. Express each of the following volumes in SI unit giving your answer in standard form(2marks)
   1. 25000cm³
      2.5×10-2m³
   2. 0.5675cm³
      5.675×10-7m³
2. State the basic law of magnetism . (1mark)
   • Like poles repel unlike poles attract.
3. The figure shows an electromagnet. State the polarities at X and Y.(2 marks)
   • X-South
   • Y-North
4. Dust particles in air appear to move randomly, explain this observation.(1 marks)
   • Due to uneven bombardment by invisible air particles or molecules in the air.
5. The diagram below shows a section of a micrometer screw gauge.
   1. State the smallest measurement that can be made by the measurement that can be made by the micrometer screw gauge. (1 mark)
      • 1/100mm or 0.01mm
   2. What is the correct reading of the micrometer screw gauge if it has an error of 0.25cm           (3 marks)
      Initials reading =16.32mm
      0.25cm=2.5mm
      Diameter=16.32−2.5=13.82mm
6. State two properties of magnetic field lines (2marks)
   • They originate from North Pole and end at the South Pole.
   • They repel each other side ways and form closed paths never intersecting other lines of forces.
   • They are closer together where the field is strongest
7. A charge of 180coloumbs flows though a lamp every minute. Calculate- the current flowing through the lamp(3marks)
   Q=It
   180C = 60I
   I=3A
8. The figure below shows part of a vernier caliper when the jaws are closed without an object between the jaws
   1. What is the value of the zero error of the calipers?(1mark)
      • −0.02mm
   2. A student used the same vernier calipers in (a) above to measure the diameter of a test tube whose actual diameter is 2.15cm. What was the reading shown by the calipers(3marks)
      2.15=reading − error
      2–15=reading + 0.02
      Reading = 2.13mm
9. Explain why repulsion is the sure test for polarity of a magnet(1mark)
   • The polarity of a magnet can be tested by bringing both its poles, in turn, adjacent to the known poles of a suspended magnet. Repulsion only occurs between the like poles of a magnet. Attraction might occur between unlike poles and a magnetic material thus repulsion is the only sure way to test for polarity.
10. Explain why a gold leaf is electroscope casing is made up of metal(1mark)
    • Metal casing is for protecting the leaf from the effects of draught.
11. Explain the difference between magnetic and non magnetic materials (2marks)
    • magnetic materials are those attracted by a magnet e.g iron
    • non magnetic materials are those not attracted by a magnet e.g plastic
12. On the graph provided, sketch a graph of density against Temperature of a given mass of water(2 marks)
    
13. State two properties of a good thermometric fluid(2marks)
    • Be easily seen (visible).
    • Expand or contract uniformly and by a large amount over a small range of temperature.
    • Not stick to the inside of the tube. (Should not wet the inside of the tube.
    • Have a wide range of temperature.
14. State one application of magnets.(1mark)
    • Magnets have a wide application in real life. For example in hospitals, they are used to remove a piece of iron from the eye.
    • They are used in making compasses, loudspeakers, telephone receivers, bicycle dynamos, generators and electric motors.
15. State the laws of reflection
    • angle of incidence=angle of reflection
    • at the point of incidence, the incident ray, reflected ray and the normal line all lie on the same plane.