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Water of mass 3kg initially at 20℃ is heated in an electric kettle rated 3.0kW. Thewater is heated until it boils at 100℃. Taking specific heat capacity of water=4200Jkg/K, heat capacity of kettle=450J/kg, specific latent heat of vapourisation of water =2.3MJ/kg, calculate;

answered Aug 18, 2021 in Physics Form 3

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Explain why it is advisable to use the pressure cooker for cooking at high altitudes.

answered Aug 18, 2021 in Physics Form 1

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The figure 4 below shows an object of mass 0.2kg whirled in vertical circle of radius 0.5m at uniform speed of 5m/s.

answered Aug 18, 2021 in Physics Form 4

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Distinguish between angular and linear velocity.

answered Aug 18, 2021 in Physics Form 3

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What is the gravitational potential energy stored in a spring when stretched through 4cm by a force of 2N

answered Aug 18, 2021 in Physics Form 1

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Figure 3 shows a small toy boat floating on water in a basin. X and Y are two points near the toy.

answered Aug 18, 2021 in Physics Form 1

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The efficiency of a pulley system is always less than 100%. State two reasons.

answered Aug 18, 2021 in Physics Form 1

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A student pulls a block of wood along a horizontal surface by applying a constant force. State the reason why the block moves at a constant.

answered Aug 18, 2021 in Physics Form 1

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State why it is necessary to leave an air space in closed glass bottle of water when it is to be kept in a refrigerator.

answered Aug 18, 2021 in Physics Form 1

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Figure 2 below shows a piece of wood fitted into a copper pipe and a piece of paper wrapped tightly around the junction.

answered Aug 18, 2021 in Physics Form 1

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State the Archimedes principle.

answered Aug 18, 2021 in Physics Form 4

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Briefly explain why rooms are at a lower level and ventilators at a higher level.

answered Aug 18, 2021 in Physics Form 1

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A mercury barometer reads 760mmHg at sealevel and 700mmHg at the top of a mountain. If the density of mercury is 13,600kg/m3 and average density of air is 1.30kg/m3, calculate the height of the mountain.

answered Aug 18, 2021 in Physics Form 1

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A solid weighs 32.5N on the surface of the moon. The force of gravity on the moon is 1.7Nkg-1. Determine the mass of the solid.

answered Aug 18, 2021 in Physics Form 1

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The figure below shows the scale of a measuring instrument when measuring the thickness of an object.

answered Aug 18, 2021 in Physics Form 1

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The flow chart below shows the large scale manufacture of ammonia gas and some ammonium compounds. Study it and answer the questions that follow.

answered Aug 17, 2021 in Chemistry Form 2

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Give two reasons why wood and charcoal are chosen for domestic heating.

answered Aug 17, 2021 in Chemistry Form 4

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Define heat value of a fuel.

answered Aug 17, 2021 in Chemistry Form 4

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The diagram below shows an energy level diagram for the formation of magnesium chloride. Study it and answer the questions that follow.

answered Aug 17, 2021 in Chemistry Form 4

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Distinguish between hydration energy and lattice energy.

answered Aug 17, 2021 in Chemistry Form 4

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