Extended Flashcards
What is that measuring tool thing called that you turn?
Vernier scale
Micrometer
Screw gauge
What is the scale on the spinning bit of the vernier scale?
10 on the spinning bit = 0.1mm
1 on the spinning bit = 0.01mm
When doing equations, time is always recorded in…
Seconds
In a thermocouple the 2 wires touching the surface are made of…
Different materials. The 2nd wire has a wire the same material as wire 1 between it and the thermocouple
What do thermocouples measure with?
Milli/voltmeter
Which way does charge go in beta ray?
Into source, opposite to the flow of electrons
Which way does charge go in alpha ray?
Same way as ray direction
State the nature of gamma rays
Electromagnetic
What happens to current through a resistor when the other resistor’s resistance decrease?
Current in whole circuit increases, which means current through resistor increases
What’s focal length?
Middle of lens to focal point
Wave speed equation?
Velocity = frequency x wavelength
Equation for specific heat capacity
E = mass x shc x change in temperature
State two ways in which the molecular structure in a liquid is different to that of a solid?
Molecules are not in fixed positions
AND
Have a random arrangement
Energy change when converting food into body temperature?
Chemical to thermal
Pressure in water
Pressure = depth x density x 10(gravity)
What could cause SHC to be too high?
Too low a change in temperature because of: poor insulation, or inefficient heater
What converts can current to dc?
Rectifier
Describe the difference in attractive forces between gas and solids
Attractive forces in gases are less than solids. This means that gas molecules are further apart than in solids
What is stored in the battery of a cellphone?
Energy
Name the process that causes a potential difference across a solenoid due to the movement of a nearby magnet
Electromagnetic induction
3 physical properties that can be used to measure temperature
Expansion of a liquid
Voltage of a thermocouple
Pressure of a gas
Working out power from force and distance
Energy (work done) = force x distance
Power = energy/time
Describe motion of molecules in a gas
Move randomly, at a range of speeds, collide with each other
Explain, in terms of molecules, what happens when temperature increases
Molecules have more energy and move quicker. The molecules collide with each other with a greater frequency
Speed of sound in gas
300 m/s
Speed of sound in solid
3000 m/s
What connects to the coil in a motor/generator
Slip rings and brushes
What stops gamma?
2cm of lead
What sort of current is produced after going through a transformer?
A.C of the same frequency
An increase in the temperature of the gas increases the pressure because…
The speed of the molecules increases
Why do things cool to the same temperature?
Conduction happens and thermal energy is transferred until the temperature is equal
What is the energy change when someone cycles up a hill?
Chemical energy to gravitational potential energy
Why is something not in equilibrium?
There is a resultant force and a resultant moment
Three man made devices that use the principle of moments?
Seesaw, doors, spanners
What’s the value of air resistance at terminal velocity?
Mass x 10
Why does sweating cool the body?
The particles that evaporate are the ones with the most energy
When they leave the temperature of the sweat decreases
Thermal energy is transferred from the body to the sweat; cooling the body
Define pressure
Force/area
Explain how a gas exerts pressure on the walls of a container
Molecules collide with the sides of the walls. This collision exerts force on the wall. This force divided by the area it occurs on equals pressure.
What does virtual mean?
The image is virtual because it cannot be seen on a screen
What happens when wavelength (but not speed) decreases?
Frequency increases
What does ionisation mean
Giving the gas molecules a charge by adding or removing electrons from the molecules
What conclusions can we make about a nucleus because it deflects an alpha ray?
The nucleus is very small compared to the rest of the atom BUT contains most of the mass
What is the height in mgh?
Height change of the centre of mass
What has the same value through two resistors when connected in series?
Current
What has the same value through two resistors when connected in parallel?
Voltage
Circle with arrow for relay circuits
Transistor
Suitable detector for radiation
Geiger
How to un charge something
Earth it
Unearth it
Move the other charged object away
One pendulum swing
From one side to the other and back again
What’s in the top of the barometer tube?
Vacuum
Why might atmospheric pressure be different?
Abnormal weather conditions
What does change of pressure cause?
Change of volume
What properties must a liquid have in a thermometer?
Expands uniformly
Expands more than glass
How to make a thermometer more sensitive?
Make capillary tube narrower
Make bulb larger
Why must glass in a thermometer be thin?
Faster flow of heat alcohol, allowing a faster response to temperature change
What happens to compressions if a wave has a higher frequency?
Compressions are closer together
What happens to layers of air at compressions when amplitude increases?
Layers become closer together
What happens to layers of air at rarefractions when amplitude increases?
Layers of air get further apart
Equation linking speed and refractive index
Refractive index = velocity in air (or vacuum) / velocity in glass
Equation linking angles of incidence, refraction and refractive index
Refractive index = sin angle of incidence / sin angle of refraction
How to make electromagnet induction more effective?
More powerful magnet
More coils in solenoid
Move magnet faster
What’s the point of the heater in a cathode-ray oscilloscope?
Heat the cathode
What’s the point of the cathode in a cathode-ray oscilloscope?
Emit electrons
What’s the point of the anode in a cathode-ray oscilloscope?
To attract the electrons, ensuring that a straight beam of electrons is produced
Describe how plates are used to bring about deflection
Potential difference across plates
Why does proton number increase by one during beta decay?
Neutron changes to proton
What stays the same during beta decay?
Atomic mass
How to increase speed of rotation of a coil in motor effect
More turns on coil More current Iron core in coil Higher voltage through coil Stronger magnet
How is energy lost from a transformer?
Heat from either coil
Sound from core
How does a transformer work (4 points)
The primary coil forms an electromagnet. The electromagnet switches poles because of the ac current. This changing magnetic field induces a current in the secondary coil. Fewer coils in secondary means the emu induced is smaller than the voltage in the primary coil.
Sound waves are longitudinal and…
Mechanical
Light waves are transverse and…
Electromagnetic
If an object is travelling at 70 m/s how many metres does it travel in 1 second?
70 metres
Why might specific heat capacity be too low?
Energy lost to surroundings
Rate of heating lower
How to give accurate results in specific heat capacity
Insulate experiment
Get heater up to temperature before inserting heater
Same starting temperature
What is meant by total internal reflection? (4)
incident ray in (more) dense medium
angle of incidence greater than critical angle
no light refracted
Angle of reflection to angle of incidence
7 electromagnetic waves
Gamma, x, infrared, radio, micro, visible, UV
What happens when an unevenly charged object is earthed, with the charged rod still nearby?
Negative part stays negative
Positive charge neutralised by electrons flowing up from the earth
Why do detectors detect radiation when there is no source?
Background radiation from soil and medical equipment
Different at different times
Why is gamma radiation not deflected by magnetic fields?
Electromagnetic radiation with no charge
Difference between deflection of alpha and beta radiation
Beta is deflected more than alpha because beta is much smaller than alpha
What electrical quantity does voltage represent
Potential difference
What electrical quantity does hz represent
Frequency
What electrical quantity do kW represent
Power
What must be earth?
Outside of product
Is surface area decreases but pressure remains the same what happens to the force?
Force decreases
Mass of trolley in relation to a force-acceleration graph.
Mass equals gradient
