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- A sample of a radioactive substance initially has 8.0 x 1025 particles. The half life of the sample is 98 seconds. Determine the number of...(Solved)
A sample of a radioactive substance initially has 8.0 x 1025 particles. The half life of the sample is 98 seconds. Determine the number of particles that will remain after 294 seconds.
Date posted: September 6, 2019. Answers (1)
- A form two student from Kimomo Secondary School found his dry cells leaking on removing from his torch. What would be the possible cause of...(Solved)
A form two student from Kimomo Secondary School found his dry cells leaking on removing from his torch. What would be the possible cause of the leakage?
Date posted: September 6, 2019. Answers (1)
- A vibrator is sending out 8 ripples per second across a ripple water tank. The ripples are observed to be 4cm apart. Calculate the velocity...(Solved)
A vibrator is sending out 8 ripples per second across a ripple water tank. The ripples are observed to be 4cm apart. Calculate the velocity of the ripples
Date posted: September 6, 2019. Answers (1)
- One of the factors that affect efficiency of a transformer is hysteresis losses. What is hyteresis losses?(Solved)
One of the factors that affect efficiency of a transformer is hysteresis losses. What is hyteresis losses?
Date posted: September 6, 2019. Answers (1)
- Give a reason why x-rays but not radio waves are used to detect fractured bones.(Solved)
Give a reason why x-rays but not radio waves are used to detect fractured bones.
Date posted: September 6, 2019. Answers (1)
- The following figure shows the path of a ray of light through a transparent material placed in air.(Solved)
The following figure shows the path of a ray of light through a transparent material placed in air.
Determine the refractive index of the transparent material
Date posted: September 6, 2019. Answers (1)
- The control grid in a cathode ray oscilloscope (CRO) is used to control the brightness of the beam on the screen. Explain how the brightness...(Solved)
The control grid in a cathode ray oscilloscope (CRO) is used to control the brightness of the beam on the screen. Explain how the brightness of the beam can be increased.
Date posted: September 6, 2019. Answers (1)
- A current of 0.7A flows through a wire when a potential difference of 0.35V is applied at the ends of the wire. If the wire...(Solved)
A current of 0.7A flows through a wire when a potential difference of 0.35V is applied at the ends of the wire. If the wire is 0.5m long and has a cross-sectional area of 8.0 x 103mm2, determine its resistivity.
Date posted: September 6, 2019. Answers (1)
- The figure below shows a positively charged metal plate with an earthing connection. State and explain the final charge of the plate.(Solved)
The figure below shows a positively charged metal plate with an earthing connection. State and explain the final charge of the plate.
Date posted: September 6, 2019. Answers (1)
- The figure below shows a load of 50N being raised by pulling it along an inclined plane of length 2.0m.(Solved)
The figure below shows a load of 50N being raised by pulling it along an inclined plane of length 2.0m.
Determine
i. The work done by the 22N force
ii. The work done against the load
iii. The efficiency of the system
Date posted: September 6, 2019. Answers (1)
- The figure below shows a buoy of capacity 40 litres and mass 10kg. It is held in position in sea water of
density 1.04g/cm3 by a...(Solved)
The figure below shows a buoy of capacity 40 litres and mass 10kg. It is held in position in sea water of
density 1.04g/cm3 by a light cable fixed to the bottom so that ¾ of its volume is below the water surface.
Determine the tension in the cable.
Date posted: September 6, 2019. Answers (1)
- The figure below shows a block with a graduated side and dimensions 4cm by 16cm, just about to be lowered
into a liquid in an overflow...(Solved)
The figure below shows a block with a graduated side and dimensions 4cm by 16cm, just about to be lowered
into a liquid in an overflow can.
During an experiment with this set-up, the following was recorded:
- The block floated with three-quarter of it submerged.
- Initial reading of balance = 0g
- Final reading of balance = 154g
Use the information to determine the density of
(i) the block
(ii) the liquid
Date posted: September 6, 2019. Answers (1)
- A bicycle wheel makes 300 revolutions per minute. Calculate the angular velocity of the wheel.(Solved)
A bicycle wheel makes 300 revolutions per minute. Calculate the angular velocity of the wheel.
Date posted: September 6, 2019. Answers (1)
- The figure below shows two masses 0.1kg and 2kg connected by a string through a hole on a smooth horizontal surface.The 0.1kg rotates in a...(Solved)
The figure below shows two masses 0.1kg and 2kg connected by a string through a hole on a smooth horizontal surface.
The 0.1kg rotates in a horizontal circle of radius 3cm. Calculate the angular velocity of the 0.1kg mass, when the system is in equilibrium.
Date posted: September 6, 2019. Answers (1)
- Three insoluble powders A, B and C of densities dA, dB and dC, such that dA>dB>dC, are mixed and put into a container.The container is...(Solved)
Three insoluble powders A, B and C of densities dA, dB and dC, such that dA>dB>dC, are mixed and put into a container.The container is then whirled in a horizontal circle as shown in the figure below.
(i) Label on the figure, the positions of the powders after some time.
(ii) Give a reason for your answer in (i)
Date posted: September 6, 2019. Answers (1)
- A ball slides off a horizontal table 4m high with a velocity of 12m/s, find;
(i) the time it takes to hit the floor. (g =...(Solved)
A ball slides off a horizontal table 4m high with a velocity of 12m/s, find;
(i) the time it takes to hit the floor. (g = 10ms-2)
(ii) the range
Date posted: September 6, 2019. Answers (1)
- A car decelerates uniformly from a velocity of 20m/s to rest in 4 seconds. It takes 4 seconds to reverse with uniform acceleration to its...(Solved)
A car decelerates uniformly from a velocity of 20m/s to rest in 4 seconds. It takes 4 seconds to reverse with uniform acceleration to its original starting point.
(i) Sketch a velocity time graph for the motion of the car.
(ii) Use your sketch in c (i) to determine the total displacement of the car.
Date posted: September 6, 2019. Answers (1)
- The figure below shows the displacement – time graph of the motion of a particle.
State the nature of the motion of the particle between?
(i)...(Solved)
The figure below shows the displacement – time graph of the motion of a particle.
State the nature of the motion of the particle between?
(i) AB
(ii) BC
(iii CD
Date posted: September 6, 2019. Answers (1)
- State the physical quantity represented by the gradient of a displacement – time graph(Solved)
State the physical quantity represented by the gradient of a displacement – time graph
Date posted: September 6, 2019. Answers (1)
- A substance of mass 2kg and specific heat capacity 400J/kg/k initially at 800C is immersed in water at 190C. If the final temperature of the...(Solved)
A substance of mass 2kg and specific heat capacity 400J/kg/k initially at 800C is immersed in water at 190C. If the final temperature of the mixture is 200C. Calculate the mass of water. (Specific heat capacity of water = 4200J/kg/k)
Date posted: September 6, 2019. Answers (1)