Physics Flashcards
Collect lost marks on IGCSE Physics
A man drops a brass key into the oil and it sinks to the bottom of the oil.
Explain how attaching the key to a piece of wood could prevent the key from sinking.
The density of the wood and the key combined is less than the density of oil.
Explain, in terms of molecules, why it is possible to compress a gas, but not a liquid.
Gas molecules are very far apart
Molecules of liquid are very close together
Evaporation occurs.
Explain, in terms of molecules, why the temperature has decreased.
Most energetic particles escape.
Less energetic particles remain.
A quantity of gas is contained in a sealed container of fixed volume. The temperature of the gas is increased. State, in terms of molecules, two reasons why the pressure of the gas increases.
Particles hit walls with more force.
Particles have more momentum.
Particles hit walls more frequently.
The sound wave passes from the sea-water into the air
State what happens, if anything, to
1. The frequency of the sound
2. The speed of the sound
Unchanged
Slower
Describe one use of optical fibres in medicine. You may draw a diagram.
Endoscope
Using a bundle of optical fibres
Doctors look inside the body
A d.c. supply is connected to the input of a transformer.
When switch S is first closed, the needle of the galvanometer deflects, then returns to zero. Explain why the brief deflection occurs.
There is a change in current.
This produces a changing magnetic field that travels to the secondary coil and causes a voltage to be induced.
A same amount of cold water as in an insulating bowl is poured into a metal
bowl.
The metal bowl is the same shape and size as the insulating bowl.
The decrease in temperature is less than before.
Explain why.
Metal is a good conductor of heat.
Metal conducts heat away from the water and into the surroundings.
Suggest why there is a current in the wire between the sphere and earth.
Electrons are transferred from the sphere to the earth
