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- The average speed of a bus travelling to Mombasa from Nairobi is 86 km/h. Calculate the
distance in metres covered by the bus in 45 minutes.(Solved)
The average speed of a bus travelling to Mombasa from Nairobi is 86 km/h. Calculate the
distance in metres covered by the bus in 45 minutes.
Date posted: April 10, 2019. Answers (1)
- An object covers a distance of 240 m in two minutes before resting for one minute. It then
continues to cover 660 m in three more...(Solved)
An object covers a distance of 240 m in two minutes before resting for one minute. It then
continues to cover 660 m in three more minutes. Calculate the average speed.
Date posted: April 10, 2019. Answers (1)
- A cyclist rides 3 km east and then turns around and rides 5 km west. Determine her
a. Distance
b. Displacement
c. Magnitude of the displacement(Solved)
A cyclist rides 3 km east and then turns around and rides 5 km west. Determine her
a. Distance
b. Displacement
c. Magnitude of the displacement
Date posted: April 10, 2019. Answers (1)
- An element x (uranium) decays by emitting two alpha particles and a beta particle
to yield element Y
(Solved)
An element x (uranium) decays by emitting two alpha particles and a beta particle
to yield element Y
(i) State the atomic number and mass number of Y
(ii) Write down the decay equation
Date posted: April 5, 2019. Answers (1)
- The half-life of a radio-active substance is 138 days. A sample of the substance has 8 x 1010 un-decayed nuclei at time t = 0....(Solved)
The half-life of a radio-active substance is 138 days. A sample of the substance has 8 x 1010 un-decayed nuclei at time t = 0. How many un-decayed nuclei will be left after 690 days?
Date posted: April 5, 2019. Answers (1)
- Radium -222 is a radioactive element with a half-life period of 38 sec. What fraction of the mass
of a sample of this element remain after...(Solved)
Radium -222 is a radioactive element with a half-life period of 38 sec. What fraction of the mass
of a sample of this element remain after 380 sec.
Date posted: April 5, 2019. Answers (1)
- Arrange the following in order of increasing frequency: Red light, Infrared radiation, X-rays,
UV radiation, Short –radio waves, TV and Fm radio waves, Am radio waves...(Solved)
Arrange the following in order of increasing frequency: Red light, Infrared radiation, X-rays,
UV radiation, Short –radio waves, TV and Fm radio waves, Am radio waves and Long radio
waves.
Date posted: April 5, 2019. Answers (1)
- The expression below is an equation for radioactive element A. Element B and C are the daughter
nuclides. A, B and C are not the actual...(Solved)
The expression below is an equation for radioactive element A. Element B and C are the daughter
nuclides. A, B and C are not the actual symbols of any of the elements
a) State what type of radioactive decay this is.
(b) What is the value of:
X……………… Y……………………
Date posted: April 5, 2019. Answers (1)
- The following is a nuclear reaction for a fusion process resulting from the reaction of polonium
with loss of beta particles(Solved)
The following is a nuclear reaction for a fusion process resulting from the reaction of polonium
with loss of beta particles
(i) Determine the values of S and T
(ii) State the source of the energy released
Date posted: April 5, 2019. Answers (1)
- One of the application of Beta emission (B) is controlling thickness gauge. Explain
how they are used for this purpose?(Solved)
One of the application of Beta emission (B) is controlling thickness gauge. Explain
how they are used for this purpose?
Date posted: April 5, 2019. Answers (1)
- Th disintegrates into radium (Ra) by emission of two alpha and two beta particles as in equation.(Solved)
Th disintegrates into radium (Ra) by emission of two alpha and two beta particles as in equation.
State
i) The atomic number of the daughter nuclide
ii) The mass number of the daughter nuclide
Date posted: April 5, 2019. Answers (1)
- The diagram below shows the paths taken by three radiations A, B and C from a radio
active isotope through an electric field(Solved)
The diagram below shows the paths taken by three radiations A, B and C from a radio
active isotope through an electric field
i) State the charge on plate Y
ii) Identify the radiation A and C
iii) Give a reason why C deviates move A
Date posted: April 5, 2019. Answers (1)
- When carrying out experiments with radio active substance one is instructed that the source
should never held with bare hands but with forceps. Give a reason...(Solved)
When carrying out experiments with radio active substance one is instructed that the source
should never held with bare hands but with forceps. Give a reason for the instruction
Date posted: April 5, 2019. Answers (1)
- Uranium 235 was bombarded with a neutron and fission took place in the following manner:(Solved)
Uranium 235 was bombarded with a neutron and fission took place in the following manner:
Determine the values of a and b
Date posted: April 5, 2019. Answers (1)
- A manufacturer wishes to check the thickness of steel sheets he produces. Explain how
this can be done using a radioactive source and a counter(Solved)
A manufacturer wishes to check the thickness of steel sheets he produces. Explain how
this can be done using a radioactive source and a counter
Date posted: April 5, 2019. Answers (1)
- Alpha particles have low penetrating power as opposed to beta particles. Give a reason for this(Solved)
Alpha particles have low penetrating power as opposed to beta particles. Give a reason for this
Date posted: April 5, 2019. Answers (1)
- What evidence supports the fact that gamma rays are not charged(Solved)
What evidence supports the fact that gamma rays are not charged
Date posted: April 5, 2019. Answers (1)
- The half life of a radioactive element is 20minutes. The mass of the element after 120
minutes is 0.03125g. Determine the original mass of the element(Solved)
The half life of a radioactive element is 20minutes. The mass of the element after 120
minutes is 0.03125g. Determine the original mass of the element.
Date posted: April 5, 2019. Answers (1)
- Determine the value of x and y in the nuclear equation below:-(Solved)
Determine the value of x and y in the nuclear equation below:-
Date posted: April 5, 2019. Answers (1)
- You are provided with the following:-(Solved)
You are provided with the following:-
- One diode
-A load resistor
- An a.c. source
- One transformer
(i) Using the above apparatus draw a circuit arrangement for half wave rectification
(ii) Explain how the circuit drawn in (i) above achieves half wave rectification
Date posted: April 5, 2019. Answers (1)