Flashcards in Deck 6 = General information test Deck (22):
The graph shows the current through a filament lamp change as the voltage increases, explain why the graph is not a straight line? (4)
-Increased voltage leads to higher current.
-Current has a heating effect in the filament / electrical energy transferred to thermal.
-Temperature (of filament) increases.
-Resistance (of filament) increases.
-Changing resistance illustrated by changing gradient of line.
Besides reducing drag, why is it important for the main body of the car to be closer to the ground?
-Center of mass is lower.
Use ideas about energy to explain why a car leaving the track at high speed rapidly decelerates through the gravel? (3)
-High speed means high KE.
-Car’s KE transferred/lost to gravel into KE of gravel (grains).
As the rope stretches the bungee jumper slows, describe fully the energy transfer that happens as the bungee jumper continues to fall towards the ground? (3)
-KE of jumper transfers to the rope.
-GPE of jumper transfers to the rope.
-potential elastic energy (in rope).
Suggest why doing two loads of washing at the economy setting would be less efficient than doing one full load? (2)
-Washing for greater/double time.
-More (heat) energy lost to surroundings/ machine.
One way of reducing the heat transfer by droughts?
-Draught excluders/door seals.
Explain how the air cavity between the two walls reduces the heat transfer from the house?
-Air is a poor conductor/good insulator.
-Reduces heat transfer by conduction.
How can you tell that the filament lamp is hotter? (1)
-Link infrared to heat radiation/energy.
How can you tell that the fluorescent lamp is more efficient at lighting the home? (2)
-All/more power output in visible spectrum.
-Visible light is the useful output energy/power.
Explain why the acceleration of the athlete decreases to zero during the race? (2)
-Reaches Terminal Velocity.
-Driving force balanced by friction.
Write down the equation that links current, voltage and resistance?
Describe how sound travels through the air and how it effects the eardrum? (2)
-Longitudinal wave or oscillations (of air particles) parallel to wave direction.
-Transfers energy to the eardrum.
If the same experiment is carried out on Earth, air Resistance affects both objects. The feather reaches the ground after the hammer, even though the force of air resistance is smaller on the feather than on the hammer. Explain why the feather reaches the ground after the hammer?
-Feather has lower mass/weight than hammer.
-Lower air resistance required to balance weight.
-Feather’s terminal velocity lower.
-Takes more time to reach the ground.
The family uses carpets and underlay to reduce the energy loss. Explain why this reduces heat loss?
-Contain trapped air.
-Air is a poor conductor / good insulator.
Use your own knowledge of forces to explain what is meant by terminal velocity? (2)
-When driving force is balanced by friction / Weight balanced by air resistance.
When Jan opens her parachute her terminal velocity changes. Describe what happens to each of the two forces acting on her and how this causes change to her terminal velocity? (4)
-Weight remains the same.
-Air resistance increase (because of larger surface area).
-Resultant force (upwards).
-Weight balanced by air resistance.
-Lower terminal velocity.
A duck is in the bath. The water now drains out of the bath. The ripples become further apart. Peter thinks this is to do with the water getting shallower. Mary thinks it is because the clockwork is running down. Comment on these views as fully as you can. (3)
-Shallower water would decrease speed of wave.
-Therefore, wavelength would decrease (as v = fλ).
-Clockwork running down leads to lower f
Therefore, λ increases.
Which measuring cylinder would give the most precise measurement? Explain your answer? (2)
-Capable of recording the smallest value / to the nearest -0.2ml
The most precise measuring cylinder may not give an accurate reading, suggest why? (1)
-Some water may already be in the cylinder.
-Surface may not be horizontal.
-Narrow tube hard to pour water into so spillage may occur.
State two conditions required for total internal reflection to take place? (2)
1. Angle of incidence must be greater than the critical angle.
2. Fiber must have a greater refractive index than surrounding medium.
Suggest one advantage of sending signals through optical fibers? (1)
-Signal faster / travels at the speed of light.