(a) Explain why bulbs in along corridor are not wired in series (2mks)
(b) An electric cooker has an oven rated 2500w, a grill rated 1500w and two plates each of 1000W. This cooker operates directly from 240v supply. What is the costs of operating all the parts at once for 30 minutes if electricity costs sh.10.00 per unit? (3mks)
(c) Study the figure below
(i) What name is given to the fitting in the diagram (1mk)
3 pin plug
(ii) Identify the parts labeled (2mks)A
Neutral wire
B
Earth wire
C
Live wire
D
Fuse
0 Comments
 Give two advantages of a circuit breaker instead of a fuse in domestic wiring (2mks)
K.C.S.E Physics Q & A - MODEL 2019PP2QN07
​Figure 3 shows a cell connected in series with an ammeter, a 2 ohms resistor and a switch.A voltmeter is connected across the cell.
​With the switch open, the voltmeter reads 1.5 V. Given that the internal resistance of the cell is 0.5 ohms , determine the ammeter reading when the switch is closed.
answer
K.C.S.E Physics Q & A - MODEL 2019PP2QN06
State the reason why the current produced by a simple cell falls rapidly when the cell is being used,
answer
K.C.S.E Physics Q & A - MODEL 2018PP2QN14
Figure 3 shows two current-carrying wires A and B passing through a cardboard.​
​On the diagram, sketch the magnetic field lines around the wires to show how the fields interact.
answer
K.C.S.E Physics Q & A - MODEL 2018PP2QN13
State the meaning of the term battery.
answer
K.C.S.E Physics Q & A - MODEL 2016PP2QN11
​A heater of resistance R1 is rated P watts, V volts while another of resistance R2 is rated 2P watts, V/2 volts. Determine R1 / R2
answer
K.C.S.E Physics Q & A - MODEL 2016PP2QN03
​Figure 4 shows a solenoid carrying an electric current.
​Sketch the magnetic field pattern inside and at the ends of the solenoid
answer
K.C.S.E Physics Q & A - MODEL 2015PP2QN18
​(a) Three resistors of resistance 2 ohms, 3 ohms and 4 ohms are to be connected to a cell such that they have the least effective resistance.
(I) Draw a circuit diagram to show how they can be connected to achieve this. (ii) Determine the least effective resistance of the three resistors.
​(b) A real object of height 1 cm placed 50 mm from a converging lens forms a virtual image 100 mm from the lens.
(i) Determine the: (I) focal length of the lens; (II) magnification. (ii) On the grid provided draw to scale the ray diagram for the set up, to show how the image is formed.
answers
K.C.S.E Physics Q & A - MODEL 2014PP2QN16
​(a) Figure 7 shows resistors R1 and R2 connected in parallel. Their ends are connected to a battery of potential difference V volts.
(i) In terms of V1, R1 and R2, write an expression for:
(I) current I, through R,. (II) current I2 through R,; (III) total current I in the circuit. 
​(b) Figure 8 shows a negatively charged rod placed near an uncharged conductor resting on an insulating support.
​(i) Show the charge distribution on the conductor.
(ii) State the effect: (I) of momentarily touching the conductor with a finger while the charged rod is still near the conductor. (II) on the charge distribution of withdrawing the negatively charged rod after momentarily touching the conductor. (iii) In the space provided, sketch a diagram to show how the charge in ii (II) would have been distributed if the conductor was a sphere.
answers
​(b)(ii) (I) The conductor loses the negative charges to earth.
(II) The conductor acquires a net positive charge/which redistributes itself. 
K.C.S.E Physics Q & A - MODEL 2014PP2QN15
​(a) One of the causes of energy loss in a transformer is heating in the coils when current flows. State:
(i)the reason why the current causes heating. (ii) how the heating can he minimized. (b) The input voltage of a transformer is 240 V and its output is 12 V. When an 80 W bulb is connected across the secondary coil, the current in the primary coil is 0.36 A
​Determine:
(I) the ratio Np/Nsof the transformer, (where Np is the number of turns in the primary coil and Ns is the number of turns in the secondary coil) (ii) the power input of the transformer. (iii) the power output of the transformer. (iv) the efficiency of the transformer.
answers
​(a) (i) resistance in the coils.
(ii) use of thicker copper wires. 
K.C.S.E Physics Q & A - MODEL 2013PP2QN16
​(a) Two points A and B have a potential difference of V volts. Q coulombs of charge flow between A and B for t seconds. Determine:
(i) the electrical energy transformed between the two points in terms of Q. (ii) the power transformed in terms of Q and t. (iii) show that the power transformed is given by P = IV.
​(b) The lighting circuit in a house has 20 lamps each rated 60 W, 240 V. Determine whether a fuse rated 4 A can be used in the circuit when all the lamps are put on.
answers
K.C.S.E Physics Q & A - MODEL 2013PP2QN09
In domestic wiring systems lamps in the lighting circuit are required to be in parallel and not in series. State two reasons for this requirement.
answer
K.C.S.E Physics Q & A - MODEL 2013PP2QN08
​Figure 4 shows a simple transformer connected to a 12 V a.c. source and an a.c. voltmeter.
​By counting the number of turns in each coil, determine the reading on the voltmeter.
answer
K.C.S.E Physics Q & A - MODEL 2013PP2QN04
​Figure 1 shows a cell of e.m.f. 2 V connected in series with a resistor R and a switch S. Voltmeters V1 and V2 are connected across the cell and the resistor respectively.
​(a) State the reading of V1 with S open.
(b) With S closed, V1 reads 1.6 V. State the reading of V2.
answer
​(a) 2V
(b) 1.6V K.C.S.E Physics Q & A - MODEL 2012PP2QN016
​(a) Figure 15, shows two coils A and B placed close to each other. A is connected to a steady D.C supply and a switch, B is connected to a sensitive galvanometer.
​(i) The switch is now closed. State the observation made on the galvanometer.
(ii) Explain what would be observed if the switch is then opened. (b) The primary coil of a transformer has 1000 turns and the secondary coil has 200 turns. The primary coil is connected to a 240V a.c mains, supply. (1) Explain how an e.m.f is induced in the secondary coil. (ii) Determine the secondary voltage. (iii) Determine the efficiency of the transformer given that the current in the primary coil is 0.20A and in the secondary coil is 0.80A.
answers
​(a) (i) Pointer deflects upto a certain; maximum value and then returns to zero;
(ii) There is a deflection in the opposite direction then back to zero; As Flux in A falls, flux in B also falls and causes induced e.m.f in the opposite directions; (b) (i) Current in the primary is constantly changing its direction; so that the resulting flux (which link coils) is constantly changing its “ direction. Therefore alternating e.m.f is induced in the secondary coil; 
K.C.S.E Physics Q & A - MODEL 2012PP2QN015
​Figure 14, shows a circuit in which a battery, a switch, a bulb, a resistor P, a variable resistor Q, a voltmeter V and two ammeters A1 and A2 of negligible resistance are connected.
​P has a resistance of 10Ç2. When the switch is closed A1 reads 0.1OA and the voltmeter reads 1.5V.
(a) Determine; (i) the current passing through P. (ii) the resistance of the bulb. (b) The variable resistor is now adjusted so that a larger current flows through A2. (i) State how this will affect the resistance of the bulb. (ii) Explain your answer in b(i). (c) A house has one 100W bulb, two 60W bulbs and one 30W bulb. Determine the cost of having all the bulbs switched on for 70 hours, given that the cost of electricity is 40 cents per kilo-watt hour.
answers
​(b) (i) the resistance of the bulb would increase;
(ii) Current is higher hence increases; temperature increased temperature results in increased resistance; 
State why alternating current (a.c) is used for transmitting electricity over long distances21/7/2020
K.C.S.E Physics Q & A - MODEL 2012PP2QN012
State why alternating current (a.c) is used for transmitting electricity over long distances
answer
K.C.S.E Physics Q & A - MODEL 2011PP2QN15
​(a) Figure 8, shows a graph of potential difference V (volts) against a current I (amperes) for a certain device.
​From the graph:
(i) state with a reason whether or not the device obeys ohms law. (ii) determine the resistance of the device at: (1) 1 =l.5A (II) I =3.5A (iii) From the results obtained in (ii) state how the resistance of the device varies as the current increases. (iv) State the cause of this variation in resistance. (b) Three identical dry cells each of e.m.f. 1 .6V are connected in series to a resistor of 11.4 ohms. A current of 0.32A flows in the circuit. Determine: (i) the total e.m.f. of the cells; (ii) the internal resistance of each cell;
answers
State the reason why electrical power is transmitted over long distances at very high voltages.20/7/2020
K.C.S.E Physics Q & A - MODEL 2011PP2QN13
State the reason why electrical power is transmitted over long distances at very high voltages.
answer
K.C.S.E Physics Q & A - MODEL 2010PP2QN17
​(a) Figure 12, shows an electrical circuit including three switches, S1, S2, S3, and three identical lamps L1, L2, L3. A constant potential difference is applied across X and Y.
​(î) Other than L1, state the lamp that will light when S1 and S2 are closed.
(ii) How does the brightness of L1 in (i) above compare with its brightness when all the switches are closed? (iii) Explain the observation in part (ii) above. (b) Figure 13, shows a cell in series with a 3ohms resistor and a switch. A high resistance voltmeter is connected across the cell. 
The voltmeter reads 1.5V with the switch open and 1.2V with the switch closed.
(i) State the electromotive force of the cell. (ii) Determine the current through the 3ohms resistor when the switch is closed. (iii) Determine the internal resistance of the cell. (c) (î) Another resistor R is connected in series with the 3ohms resistor so that a current of 0.15A flows when the switch is closed. Determine the resistance of R.
answers
K.C.S.E Physics Q & A - MODEL 2009PP2QN15
​ Figure 9 shows the graph of the relationship between current I and potential difference V for two trungsten filament lamps X and Y. The normal working voltages for the lamp X and lamp Y are 2.5V and 3.0V respectively.
​(b) Determine the resistance of lamp X at the normal working voltage
(c) The lamps are now connected in a series circuit in which a current of 0.4 A flows. Find the potential differences across lamp Y (d) Determine the power at which lamp Y operates under normal working voltage
answers
K.C.S.E Physics Q & A - MODEL 2009PP2QN08
​Figure 3 shows part of an electrical circuit. The current through the 18ohms resistor is observed to be 2A.
​State the value of the current through each of the 10 ohm resistors
answer
K.C.S.E Physics Q & A - MODEL 2008PP2QN17
​(a) Three resistors of resistance 2.0 ohms, 4.0 ohms and 6.0 ohms are connected together in a circuit.
Draw a circuit diagram to show the arrangement of the resistor which Gives (i) Effective resistance of 3.0 ohms (ii) Minimum resistance (b) In figure 11 the voltmeter reads 2.1 V when the switch is open. When the switch is closed, the voltmeter reads 1.8 V and the ammeter reads 0.1A. 
Determine:
(i) The e.m.f of the cell (ii) The internal resistance of the cell (iii) The resistance of the lamp
answers
K.C.S.E Physics Q & A - MODEL 2008PP2QN10
A heating coil is rated 100W, 240V. At what rate would it dissipate energy if it is connected to a 220V supply?
answer
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