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X lower than Y (Y higher than X) Dull black surface emits more radiant heat than shiny surface.
sharon kalunda answered the question on September 30, 2019 at 08:47
- The figure below shows an air balloon and a wooden block at equilibrium on a hot day.Explain how the equilibrium would be affected when the...(Solved)
The figure below shows an air balloon and a wooden block at equilibrium on a hot day.Explain how the equilibrium would be affected when the weather suddenly becomes cold.
Date posted: September 30, 2019. Answers (1)
- Figures 2a and 2b below shows a spring when carrying different masses.(Solved)
Figures 2a and 2b below shows a spring when carrying different masses.
i) the elastic constant of the spring.
ii) the length of the unloaded spring.
Date posted: September 30, 2019. Answers (1)
- The figure below shows a top view of two steel needles floating on water surface at a distance x metres apart.(Solved)
The figure below shows a top view of two steel needles floating on water surface at a distance x metres apart.
Very hot water is now poured at point P between the two needles. Explain any change in the distance x.
Date posted: September 30, 2019. Answers (1)
- The figure below shows a battery of e.m.f 12V and internal resistance of 2 ohms connected to resistors and an ammeter.(Solved)
The figure below shows a battery of e.m.f 12V and internal resistance of 2 ohms connected to resistors and an ammeter.
i) Determine the ammeter reading when the switch S, is open.
ii) Find the ammeter reading when the switch is closed.
Date posted: September 30, 2019. Answers (1)
- In an X-ray tube, the accelerating voltage is 100KV.(Solved)
In an X-ray tube, the accelerating voltage is 100KV.
i) Calculate the kinetic energy of the electrons arriving at the target (take e = 1.6 x 10-19C)
ii) If 0.5% of the kinetic energy is converted to X-rays, determine the minimum wavelength of the emitted X-rays (take h = 6.63 x 10-34Js and C = 3.0 x 108m/s)
Date posted: September 30, 2019. Answers (1)
- You are provided with the following apparatus used for studying charging of a capacitor. An uncharged capacitor, voltmeter, milliameter, 6V battery, connecting wires, a switch...(Solved)
You are provided with the following apparatus used for studying charging of a capacitor. An uncharged capacitor, voltmeter, milliameter, 6V battery, connecting wires, a switch and a load resistor R.
i) Draw a circuit diagram that can be used to charge the capacitor.
ii) Use the circuit diagram drawn above to explain how the capacitor gets charged.
iii) State the purpose of resistor R.
Date posted: September 30, 2019. Answers (1)
- The distance of separation between the plates of a certain capacitor is reduced. State how this affects the capacitance of a capacitor.(Solved)
The distance of separation between the plates of a certain capacitor is reduced. State how this affects the capacitance of a capacitor.
Date posted: September 30, 2019. Answers (1)
- A house has three rooms each with two 240V, 60W bulbs. If the bulbs are switched on from 7.00p.m to 10.00pm daily.(Solved)
A house has three rooms each with two 240V, 60W bulbs. If the bulbs are switched on from 7.00p.m to 10.00pm daily.
i) Calculate the power consumed per day in kilowatt-hours.
ii) Find the cost per week for lighting these rooms at sh.6.30 per kilowatt hour.
Date posted: September 30, 2019. Answers (1)
- Uranium -234 undergoes a radioactive decay represented by the equation shown below.(Solved)
Uranium -234 undergoes a radioactive decay represented by the equation shown below.
Find the value of a and b
Date posted: September 30, 2019. Answers (1)
- Given that the wavelength of a certain electromagnetic wave is 7500cm, determine its frequency. (Take the speed of light in a vacuum as 3.0 x...(Solved)
Given that the wavelength of a certain electromagnetic wave is 7500cm, determine its frequency. (Take the speed of light in a vacuum as 3.0 x 108m/s)
Date posted: September 30, 2019. Answers (1)
- The figure below shows an image I formed by an object placed in front of a convex mirror. C and F are the centre of...(Solved)
The figure below shows an image I formed by an object placed in front of a convex mirror. C and F are the centre of curvature and principal focus of the mirror respectively. Using appropriate rays locate the object position.
Date posted: September 30, 2019. Answers (1)
- The figure below shows part of an electric circuit. The charge stored in the 9µF capacitor is 1.4 micro coulombs(Solved)
The figure below shows part of an electric circuit. The charge stored in the 9μF capacitor is 1.4 micro coulombs
Determine the p.d across the 5μF capacitor.
Date posted: September 30, 2019. Answers (1)
- The figure below shows water waves travelling from region A through B to C in a ripple tank.(Solved)
The figure below shows water waves travelling from region A through B to C in a ripple tank.
On the same diagram, complete the figure to show incident waves at region A and after crossing the boundary to C.
Date posted: September 30, 2019. Answers (1)
- A coin is placed at the bottom of a beaker filled with water to a height of 2.4cm as shown in the figure below. Given...(Solved)
A coin is placed at the bottom of a beaker filled with water to a height of 2.4cm as shown in the figure below. Given that the refractive index of water is 1.33, determine the apparent depth of the coin.
Date posted: September 30, 2019. Answers (1)
- A certain car battery is rated 30Ah. Determine the amount of current it can supply in 10 minutes.(Solved)
A certain car battery is rated 30Ah. Determine the amount of current it can supply in 10 minutes.
Date posted: September 30, 2019. Answers (1)
- A soft iron bar AB is placed in a magnetic field of a horse shoe magnet as shown below.(Solved)
A soft iron bar AB is placed in a magnetic field of a horse shoe magnet as shown below.
What are the polarities of A and B.
Date posted: September 30, 2019. Answers (1)
- State two differences between sound waves and microwaves.(Solved)
State two differences between sound waves and microwaves.
Date posted: September 30, 2019. Answers (1)
- A current carrying wire is placed above a compass needle as shown in the figure below.If the current flows in the direction A to B,...(Solved)
A current carrying wire is placed above a compass needle as shown in the figure below.If the current flows in the direction A to B, show in the diagram the deflection of the compass needle.
Date posted: September 30, 2019. Answers (1)
- The figure below shows a bulb hydrometer.(Solved)
The figure below shows a bulb hydrometer.
i) State the principle in the hydrometer.
ii) Explain why the hydrometer has a weighted bulb and narrow stem.
Date posted: September 30, 2019. Answers (1)
- Give a reason why when a passenger jumps from a floating boat, the boat moves backwards.(Solved)
Give a reason why when a passenger jumps from a floating boat, the boat moves backwards.
Date posted: September 30, 2019. Answers (1)