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Figure 5 shows a narrow beam of x-rays passing between two metal plates in air. The plates are connected in series with a switch, a cell and a milliammeter
It is observed that when the switch is closed a current flows in the milliammeter. Explain this observation.
Date posted:
June 6, 2017
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Figure 18 shows the parts of an x-ray tube.
(a) Explain why:
(i) A potential difference is applied to the filament.
(ii) A high potential difference is applied between a cathode and the anode.
(iii) Most of the tube is surrounded by lead.
(b) State how the resulting x -rays are affected by increasing the potential difference between the anode and the cathode.
Date posted:
June 6, 2017
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Figure 13 shows the features of an X-ray tube.
(i) Name the parts labeled A and B.
(ii) Explain how a change in the potential across PQ changes the intensity of the X -rays produced in the tube.
(iii) During the operation of the tube, the target becomes very hot. Explain how this heat is caused.
(iv) What property of lead makes it suitable for use as shielding material?
Date posted:
June 6, 2017
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Figure 10 shows the waveform of a signal applied at the y - plates of an oscilloscope whose time-base is switched to the scale of 2 milliseconds per centimeter.
Determine:
(i) The period of the signal;
(ii) The frequency of the signal.
Date posted:
June 6, 2017
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Figure 9 shows a cathode ray tube in which a beam of electrons is cast on the screen.
(i) State how electrons are produced in the tube.
(ii) state how electron beam is detected.
(iii) State the reason for having a variable potential difference (p.d) at the: (I) grid (II) anodes
Date posted:
June 6, 2017
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Figure 10 shows the main features of a cathode ray oscilloscope (CRO).
(i) Name the part labeled M and N.
(ii) Explain how electrons are produced in the tube.
(iii) State why the tube is highly evacuated.
Date posted:
June 6, 2017
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Figure 14 (a) is a diagram of a cathode ray tube. M and N are parallel vertical plates.
When switch S is open, a spot is seen at the centre of the screen as shown in Figure 14
(i) State what happens to the sport when S is closed.
(ii) State what would happen to the spot if the potential difference across MN is increased
Date posted:
June 6, 2017
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Figure 14 shows the features of a cathode ray tube.
(i) Name the parts labeled A and B.
(ii) Explain how the electrons are produced in the tube.
(iii) State two functions of the anodes.
(iv) At what part of the cathode ray tube would the time be connected?
(v) Why is a vacuum created in the tube?
Date posted:
June 5, 2017
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Figure 6 shows a tube for investing the properties of a beam of electrons. Use the information in the figure to answer the question.
What property of the beam of electrons shows that the electrons are traveling at a very high speed?
Date posted:
June 5, 2017
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Figure 3 shows the main features of a cathode ray tube (CRT) of a cathode ray oscilloscope (CRO).
(i) Describe how the electrons are produced in the tube.
(ii) State and explain the function of the grid.
(iii) State what would be observed on the screen if an a.c voltage is connected across the y-plates.
Date posted:
June 5, 2017
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Figure 12 shows a section of a house wiring system.
(i) Name:
the circuit labeled P.
the terminals labeled X and Y.
(ii) I. State the purpose of R in the circuit.
II. Give a reason why R is connected to Y but not to X.
(iii) Why is the earthing necessary in such a circuit?
Date posted:
June 5, 2017
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Figure 17 shows the electric wiring of an electric heater. A, B, C are the mains wires.
Identify A, B and C.
Date posted:
June 5, 2017
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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.
Date posted:
June 5, 2017
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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 observations made on the galvanometer.
(ii) Explain what would be observed if the switch is then open.
Date posted:
June 5, 2017
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Figure 6 shows a horizontal conductor in a magnetic field parallel to the plane of the paper.
State the direction in which the wire may be moved so that the induced current is in the direction shown by the arrow.
Date posted:
June 5, 2017
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Figure 5 shows a magnet being moved towards a stationary solenoid. It is observed that a current flows through the circuit in a direction Q to P.
Explain: (i) How the current is produced
(ii) Why the current flows from Q to P.
Date posted:
June 5, 2017
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Figure 12 shows two circuits close to each other.
When the switch is closed, the galvanometer shows a reading and then returns to zero. When the switch is then opened, the galvanometer shows a reading in the opposite direction and then returns to zero. Explain these observations.
Date posted:
June 5, 2017
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Figure 13 shows a simple microphone in which sound waves from the person talking cause the cardboard diaphragm to vibrate.
(i) Explain how a varying current is induced in the coil when the diaphragm vibrates
(ii) State two ways in which the induced current in (i) above can be increased.
Date posted:
June 5, 2017
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Figure 10 shows a simple electric generator.
Name the parts labeled P and Q
Date posted:
June 5, 2017
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In the set up in Figure 19, the magnet is moved towards the coil and stopped when inside the coil.
It is observed that the galvanometer deflects to one side and then goes back to zero. Explain this observation.
Date posted:
June 5, 2017
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Figure 7 shows pendulum A and pendulum B freely suspended between the poles of identical magnets. Pendulum A is made of thick copper plate while B is made a copper plate with slots.
When the two are set to swing, it is observed that A slows down faster than B Explain this observation.
Date posted:
June 5, 2017
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Two identical copper coils P and Q are placed close to each other as shown in Figure 17. Coil P is connected to a D.C power supply and coil Q is connected to a galvanometer, G. Use this information to answer questions (a) and (b).
(a) State and explain what would be observed on the galvanometer immediately the switch S is closed.
(b) State with reason the difference that would be noted in the observation made in question (a) if the number of turns in coils Q were doubled.
Date posted:
June 5, 2017
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Figure 15 shows a wire XY placed in a magnetic field.
State the direction in which the wire must be moved for the current to move in the direction shown
Date posted:
June 5, 2017
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Figure 6 represents a step-down transformer with 500 turns in the primary and 50 turns in the secondary. The turns are wound uniformly on the core. The lengths of PQ and QR are indicated.
Determine the p.d across PQ.
Date posted:
June 5, 2017
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Table 1 shows radiations and their respective frequencies.
Arrange the radiations in the order of increasing energy.
Date posted:
June 5, 2017
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The chart below shows an arrangement of different parts of the electromagnetic spectrum.
Name the radiation represented by A.
Date posted:
June 5, 2017
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Table 1 carries information on the type of radiation, detector and use for some of the electromagnetic radiations. Fill in the blanks.
Date posted:
June 5, 2017
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Figure 11 shows a test-tube whose cross-sectional area is 2 cm2 partially filled with lead shot floating vertically in water.
(i) Determine the: volume of the water displaced;
(ii) Determine weight of water displaced.
(iii) State the combined weight of the test-tube and the lead shot.
Date posted:
June 5, 2017
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Figure 13 shows a hydrometer with a thin stem floating in water in a beaker.
State with a reason what is observed on the hydrometer when the temperature of the water is raised.
Date posted:
June 5, 2017
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Figure 13 shows a log of wood of mass 20 kg submerged in water in a pond and held in position by a string fixed to the bottom of the pond.
Given that the density of water is 1000 kgm -3 and that of wood is 800 kgm -3, determine the;
(i) volume of the log
(ii) Upthrust of the log
(iii) Tension in the string.
Date posted:
June 5, 2017