-
A radioactive element decays to 1/128 of its original activity after 49 days. Determine its
half –life
Date posted:
April 5, 2019
-
The figure shows the circuit of a modern X-ray tube
Name the part labeled C and state its function
Date posted:
April 5, 2019
-
An x-ray tube is operating with an anode potential of 12Kv and a current of 10.0m.A:
(i) Calculate the number of electrons hitting the anode per second
(ii) Determine the velocity with which the electrons strike the target
Date posted:
April 5, 2019
-
Three identical bulbs are connected in series with a battery of dry cells. At first the bulbs
shine brightly but gradually become dimmer. Using the same cells, explain how you
would increase the brilliance of the bulbs
Date posted:
April 5, 2019
-
A girl opened up a used up dry cell and found the following:
i) The zinc casing was ‘eaten away’
ii) The cell was watery
Name the cell defect
Date posted:
April 5, 2019
-
State one reason why colour televisions have a higher power rating than black and white
televisions
Date posted:
April 5, 2019
-
The figure shows a simple cell made of copper and zinc electrodes dipped in dilute
sulphuric acid.
a) Identify the cathode
b) If a voltmeter is connected across the rods the reading is observed to reduce with time.
State two causes of this observation
Date posted:
April 5, 2019
-
The figure below shows the set up for a simple cell.
a) Name the Electrode A and the solution B
b) State two reasons why the bulb goes off after a short time
Date posted:
April 5, 2019
-
Distinguish between Topping and Dopping
Date posted:
April 5, 2019
-
Explain why eight 1.5V cells arranged in series to give a total of 12V cannot be used to start
a car. But car battery of 12V starts a car
Date posted:
April 5, 2019
-
Explain how conductivity of a semiconductor changes with increase in temperature
Date posted:
April 5, 2019
-
The diagram below shows a simple cell:-
(i) Name z and solution y
(ii) Name and explain the defect that occurs at plate z
(iii) Give one method of preventing the defect that occurs at the copper plate
Date posted:
April 5, 2019
-
The diagram below shows a wrongly wired three pin plug.
(i) Indicate in the diagram above the correct colors for the wiring
(ii) State the use of device marked X
Date posted:
April 5, 2019
-
The figure below represents part of an electric cooker coil.
i) State why the part labeled W is coiled
(ii) State the property of material X that makes it suitable for its use
Date posted:
April 5, 2019
-
The diagram below represents a cathode ray oscilloscope (CRO)
i) Name the parts labeled A and B
ii) What are the functions of C and D?
iii) State how electrons are produced
iv) Give a reason why the tube is evacuated.
Date posted:
April 5, 2019
-
State one reason why a C.R.O is a more accurate voltmeter than a moving coil voltmeter
Date posted:
April 5, 2019
-
An electric kettle is rated 3KW, 250V. Determine the resistance of the coil
Date posted:
April 5, 2019
-
Given that a lamp is rated 45W 240V. Calculate the resistance of the heating element.
Date posted:
April 5, 2019
-
What is the relationship between periodic time and frequency of a progressive wave?
Date posted:
April 5, 2019
-
The figure below shows water waves crossing a boundary between deep and shallow water
Complete the diagram to show the wave in the deep region.
Date posted:
April 5, 2019
-
How many cubic centimeters make a gram?
Date posted:
April 5, 2019
-
The figure below shows two loudspeakers L1 and L2 connected to a signal generator.
An observer walks along the line 0-01 (equidistant from L1 and L2) and another along the
Line AA1.Explain the observation made by each and give reasons to your answer
Date posted:
April 5, 2019
-
The diagram below represents plane wave fronts produced in a ripple tank.
Given that the distance AB is 15 cm, determine the wavelength of the wave
Date posted:
April 5, 2019
-
Calculate the pressure of the gas supply (Atmospheric pressure = 1.0x105Pa)
Date posted:
April 5, 2019
-
Water of mass 200g at temperature of 60°Cis put in a well lagged copper calorimeter of mass
80g. A piece of ice at 0° C and mass 20g is placed in the calorimeter and the mixture stirred
gently until all the ice melts. The final temperature, T, of the mixture is then measured.
Determine:
i) The heat absorbed by the melting ice at O°C
ii) The heat absorbed by the melted ice (water) to rise to temperature T (answer may be
given in terms of T)
iii) The heat lost by the warm water and the calorimeter (answer may be given in terms of T)
iv) The final temperature of the mixture
Date posted:
April 5, 2019
-
The figure below shows to light pith balls arranged as shown.
State what is observed when air is blown on the outer sides of the pith balls.
Date posted:
April 5, 2019
-
A person’s lung pressure as recorded by a mercury manometer is 90 mm Hg. Express this
pressure in SI units.
Date posted:
April 5, 2019
-
The graph below represents a graph of stopping potential Vs , V against frequency f, Hz
Use the graph to determine:
(i) The threshold frequency of the metal
(ii) Plank’s constant
(iii) Work function of the metal
Date posted:
April 5, 2019
-
State and explain two features of a hydrometer that make it sensitive in its function
Date posted:
April 5, 2019
-
The figure below shows a balloon carrying hydrogen gas 3m3 of density 0.09kgm-3. The mass
of the balloon fabric is 2kg and the density of air is 1.25kgm-3
i) Determine the tension in the string
ii) If the string is suddenly cut, calculate the acceleration of the balloon upwards
iii) What is the maximum mass of the equipment the balloon can lift at a constant velocity
Date posted:
April 5, 2019