K.C.S.E Physics Q & A - MODEL 2019PP2QN18
(ii) Describe how a magnet can be demagnetised using the electrical method.
(b) You are provided with two iron bars P and Q. One of the bars is magnetized while the other is not. Explain how themagnetized bar can be identified without using a magnet or magnetic material. (c)Figure 12 shows two identical copper coils X and Y placed close to each other. Coil X is connected to a DC power supply while coil Y is connected to a galvanometer. 
​Explain what is observed on the galvanometer When the Switch is closed.
(ii) State What is observed on the galvanometer when the switch is opened. (iii) State what wou1d be observed if the number of turns in coil Y is doubled.
answers
​(a) Place the bar magnet inside a solenoid placed in the an East-West direction then pass an alternating current through the solenoid
(b) Suspend each of the bars through its center of gravity and set it swinging in a horizontal plane shows a vertical axis through its centre The magnetized bar will always come to rest in a north-south direction (c) (i) The galvanometer pointer first deflects then moves back when the switch is closed a current builds up in a coil X and due to change influx linkage an emf is induced in coil Y making an induced current to flow through the galvanometer during the time current in coil X is rising. When current through coil X is steady no induced current flows through the galvanometer since there is no change in flux linkage Therefore pointer deflects back (ii) Pointer deflects in the opposite direction. (iii) Magnitude of deflection increases
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K.C.S.E Physics Q & A - MODEL 2019PP2QN04
​Figure 2 shows an incomplete circuit for an electromagnet.
​(a) Complete the diagram to show how a battery should be connected at A so that the polarities at P and Q are South and North respectively.
(b) State two ways in which the strength of the electromagnet in (a) can be increased.
answers
​(b) Increasing the number of turns in the coil
Increasing the current (or number of cells)
K.C.S.E Physics Q & A - MODEL 2019PP2QN03
State two properties of magnetic field lines around a bar magnet.
answers
K.C.S.E Physics Q & A - MODEL 2018PP2QN03
​Figure 1 shows a bar magnet AB suspended by a string.
​When the North pole of another magnet is brought close to end A, there is repulsion State the polarity of end B.
answer
K.C.S.E Physics Q & A - MODEL 2018PP2QN02
State one characteristic of soft X-rays that distinguish them from hard X-rays.
answer
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M.A NyamotiMy passion is to see students pass using right methods and locally available resources. My emphasis is STEM courses |
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