# FORM 1 END OF TERM 3 2022 Exam-PHYSICS Answers

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END OF TERM 3 2022

FORM 1 PHYSICS MARKING SCHEME PAPER

SECTION A – 40 MKS

1.         The study of matter in relation to energy.      1 mk

2.         Career opportunities.

– Engineering (mechanical, electrical, civil, electronics etc)

– Physics teacher

– Pilot.

– Computer scientist.

– Surveyor.                              (any other relevant)    (any three)  (1 x 3)

Both correct – one mark.

only one correct – zero

4.              m    = 40 g              or                     m = 40 g

= 0.04 kg                                 r  = (50 – 40)

v     = 50 – 40                                     = 10 ml

= 10 ml                                                   = 10 cm3

= 0.0000 1 m3

z     =     0.04                                  z = 40 = 4 gcm -3

0.00001                                     10

= 4000 kg /m3                             = 4,000 kgm-3

5.(a)     Presence of impurities.

(b)     Molecule D experiences equal forces in all directions hence zero resultant  force.

The surface molecules A, B and D are only pulled inwards and no outward force for

balancing hence under tension.

Cohesive force.

7.

Density of mixture = mass of mixture

Volume of mixture

Mass of fresh water = 1800 x 1 =1800g

Mass of sea water = 2200 x 1.025 = 2255g

Density of mixture = 2255 + 1800

1800 + 2200

= 1.01375g/cm3

8.         Absence of atmospheric pressure.

9.         Concrete and steel have the same linear expansivity.  They expand and contract at the

same rate without breaking.

10.       The flask receives the heat first and expands increasing its capacity later the heat reaches

the liquid which expands at a faster rate than the glass.

11.       Alcohol..

12.(a)   Large intermolecular distances.

(b)    (i)         To focus light into the smoke cell.

(ii)        To magnify the smoke particles.

(iii)       To illuminate the smoke particles to make them more visible.

(c)      Movement of molecules from a region of high concentration to a region of low concentration.

13.       – Convection requires a medium but between the sun and the atmosphere there is a vacuum.

– Hot particles move upwards from the source.

14.       – Length of the rod.

– Thickness / cross-section area of the rod.

– Temperature difference.

(reject type of motorial & amount of heat produced by the heater)

15.  Force is defined as a pull or a push

S.I units = Newton (N)

(b) – can make objects change direction of motion

-Can make a stationary object start moving or increase the sped of moving object/cause acceleration

-Slows down or stop a moving object

-Distort (change shape) of an object

SECTION B (30 MKS)

16.       (a)

3

17.(a)   Wax B – Wood is a poor conductor and all the heat absorbed by  the rod is used for

melting the wax but the metal block conducts all the heat away.

(b)     Thermometer A

Dull surfaces are better emitters of  heat that shinny surfaces.

(c)(i) To make thermometer more accurate / sensitive.

(ii)  Quick acting /quick transmission of heat, to the mercury.

(ii)  To magnify the scale.

(d)   – Has uniform expansitity.

– Has does not wet the surface.

– It is visible/opaque.

– Good conductor of  heat.

– Has wide range of temperature

– Very sensitive to heat.                      (any three)

18.  The S.I. unit of measuring weight is Newton and not Kilogram.

19.  1 palm – Length is 15cm long

10 palm – lengths

= (10 x 15)cm

= 150  =           1.5m

100

20.  – Hold the rod upright and measure its length using the tape measure.

– Measure  the length of its shadow

– Measure the length of the shadow of a tree in the school compound

– Then relate the height of the tree from:

Height of tree

Height of rod

= Length of the shadow of the tree

Length of the shadow of the rod

21.  Mass of H2O – 40 – 20 = 20g = 0.02kg

Density of H2O – 1000kg

Volume of H2O = 0.02

1000  =  0.00002m3

Mass of liquid x 50g – 20g = 30g = 0.03kg

Volume = -.0002

Density of liquid = 1500kg/m3