Paper 1 Flashcards
(26 cards)
In a thermistor, what happens to voltage when temperature decreases
Resistance increases causing a decrease in current resulting in a decrease in voltage
How will a black surface compare to a white surface in terms of thermal energy transfer as they come in line with the sun
Black surface will have a greater temperature as it absorbs more heat than the white surface which reflects the heat
No conduction or convection will occur
Both bars increase in temperature when they face the sun
Black bar will lose temperature faster as it is a better emitter
Explain why a straight line does not obey Hooke’s law
No elastic limit reached
Straight line
Extension is proportional to force applied until a point (elastic limit)
When temperature decreases, what happens to the pressure in a balloon
It decreases as gas particles have less kinetic energy so they collide in to the balloon less frequently, with less strength and with a decreased force per unit squared
When there is a current in the coil of an electric motor, why does it start to rotate
The coil has a magnetic field and these fields start to interact
A force is produced
The force on opposite sides are opposite directions
Motor effect
what does a graph require to show a proportional relationship
a line through the origin
how do you convert Celsius to kelvin
+ 273
how does a soft material in front of a car affect the velocity-time graph after it crashes
decreases the acceleration and the gradient as time of collision is increased
why does the voltmeter change when a magnet is brought near to the wire
the magnet cuts the field lines and induces a voltage
what precautions must be taken when disposing radioactive waste
waste site security
rust proof containers which are expensive yet strong
dilution in sea water
leakage in water table
why is work done greater than GPE store when a car moves up a slope
energy is lost to surroundings
friction means increased work reqqiored
describe how voltage across a variable resistor changes if mass is added to an elastic string
I=VR so increased R
decreased current causes a decrease in voltage
total v is constant so increased v for the streched
how does a loudspeaker produce sound
a.c. current flows through the wire
motor effect
coil moves back and forth causing the cone to vibrate
longitudinal sound waves are produced
what is background radiation
ever present radiation from environmental sources
how to measure density of a hailstone
measure mass using a balance
measure diameter using a ruler
take repeats and record average
as a trolley moves through a magnetic field, explain why the sign of the voltmeter changes as the trolley moves backwards and forwards
trolley changes direction
induction depends on direction of relative motion
voltage changes direction, voltmeter depends on the direction of voltage
Describe how the processes of energy release in stars and reactors are different
Stars - fusion, smaller, lighter nuclei are joined together
Reactors - fission, larger heavier uranium nuclei are split apart
How is voltage effected when temperature decreases across a fixed resistor
Resistance increases as both current and voltage decrease
V = ir
How do gas particles exert pressure on the walls of a chamber
Kinetic energy so move around
They exert a force on the walls as they collide with the wall
Pressure=force/area
Why does a ray of light not change direction when it enters the atmosphere
Angle of incidence is 0
There is no refraction
So angle of refraction = 0 too
How does a generator produce a voltage
Coil rotates and cuts magnetic field lines
How does a loudspeaker convert a.c. Signals into a sound wave
Speaker has a current
Magnetic field lines interact with one another
A force is exerted on the speaker
A.c. Current changes direction
Force changes direction
Causing cone to vibrate
State a similarity between an artificial satellite’s orbit and a moon’s orbit
Both orbit a planet
State a difference between an artificial satellite’s orbit and a planet’s orbit
Artificial is faster
