K.C.S.E Physics Q & A - MODEL 2000PP2QN07
(a) Explain how a p- type semiconductor is made from a pure a semiconductor
(b) The curves in fig 10. Show the output characteristics of a n – p-n transistor in common emitter mode. The p.d of the battery, Vcc is 9.0V and the load resistors RL is 1.8 kohms
i. Draw the circuit diagram for the experiment set- up that may be used to obtain the curves in the figure.
ii. Given that ohm's law for the circuit is VCE = Vcc – IcRL, draw on the same axes, the load line for the circuit ( hint: load - line passes through. (VCE = 0 and Ic = 0)
Drawing load line on graph (see graph)
When IB = 30μA, An alternating signal is fed into the base so that the base current changes by ± 20μA. Use the graph to determine the corresponding change in collector current Ic and hence determine the current gain beta
K.C.S.E Physics Q & A - MODEL 2000PP2QN06
a) State the necessary conditions for interference to occur in waves
b) Fig 9. Drawn to scale of 1: 200 shows two speakers L1 and L2 connected to a signal generator (not shown) producing sound waves of frequency 350Hz. An observer walking along PQ hears loud and low sounds at alternative positions.
(i) Explain how the observations made are caused
(ii) At point O a loud sound is heard and at point A, the next loud sound is heard. Use this information and the diagram to determine the velocity of sound in air.
(iii) State and explain the effect of increasing the frequency of the signal generator on the distance OA.
K.C.S.E Physics Q & A - MODEL 2000PP2QN05
(a) Fig 8 shows a container with small holes at the bottom in which wet clothes have been put. When the container is whirled in air at high speed as shown, it is observed that the clothes dry faster.
Explain how the rotation of the container causes the clothes to dry faster.
(b) (i) A glass block of mass 100g is placed in turn at various distances from the centre of a table which is rotating at constant angular velocity. It is found that a distance of 8.0 cm from the centre, the block just starts to slide off the table. If the force of the friction between the block and the table is 0.4 N determine.
(I) The angular velocity of the table
(II) The force required to hold the block at a distance of 12 cm from the centre of the table.
(ii) A glass of mass 200 g is now placed at a distance of 8.0 cm from the centre of the table in (i) above, and the table rotated at the same constant angular velocity. State with a reason whether or not the block will slide.
K.C.S.E Physics Q & A - MODEL 2000PP2QN04
(a) (i) State one property of soft iron that makes it suitable for use as a transformer core.
FORM I - PHYSICS SYLLABUS
FORM II - PHYSICS SYLLABUS
FORM III - PHYSICS SYLLABUS
FORM IV - PHYSICS SYLLABUS
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