IGCSE revision U1 - U6

U1 Only one statement is correct or incorrect. Identify which one.

• a) We measure irregular solid volumes using a displacement can.
• b) A meter has 10^9 nanometers.
• c) We measure the density of water using a Densiometer.
• d) We measure weight using a Newtonmeter.

Answer explanation

densiometer actually exists, it measures the thickness of forest canopy. The rest are all true.

U2 Only one statement is correct or incorrect. Identify which one.

• a) Impulse = force x distance.
• b) The two kinds of solid friction are Static and Drag.
• c) Floating has a net upward force.
• d) Energy is a scalar magnitude.

Answer explanation

Solid frictions are static and dynamic, impulse = Fxt, and floating is balanced.

U3 Only one statement is correct or incorrect. Identify which one.

• a) Hookes law can always be applied to all elastic objects.
• b) A barometer measures excess pressure.
• c) Boyle´s law can always be applied as long as it is an ideal gas.
• d) 1bar = 10^5Pa

Answer explanation

Hooke only if under the proportionality limit, boyles law if Temperature doesnt change, and barometer measures atmospheric pressure.

U4 Only one statement is correct or incorrect. Identify which one.

• a) Efficiency = E coming out / E total coming in.
• b) Power = velocity x force.
• c) A thermal power station converts Echemical --> Ethermal --> Ekinetic --> Eelectrical.
• d) We can calculate efficiency using a Sankey diagram.

Answer explanation

Useful energy coming in. The rest are true.

U5 Only one statement is correct or incorrect. Identify which one.

• a) A bimetal strip is usually used to measure temperature.
• b) White is the object that best absorbs infrared.
• c) Thermal energy = mass x latent heat capacity x increase in Temperature.
• d) Evaporation happnes faster when there is +Temperature, +Wind, +Surface, and -Humidity.

Answer explanation

Bimetal strips are not very precise and are used as relay switches or thermostats, not thermometers (this is usually a thermocouple). Black matt is best absrober and emitter. Thermal energy with temperature increase needs thermal heat capacity, not latent.

U6 Only one statement is correct or incorrect. Identify which one.

• a) An oscilloscope is an apparatus that makes a graph of wave amplitude over distance.
• b) The timbre is based on the overtones of a sound.
• c) Rarefactions show in a pressure - time graph as troughs of the wave.
• d) Sound travels faster in denser and hotter materials.

Answer explanation

Oscilloscopes show amplitude over time, not distance.