Paper 2 Flashcards
Suggest why a low Power is good for Bluetooth in mobile phones
So the power is not too great so the phone will not overheat
Give two factors that affect the momentum of to bumper cars crashing into each other
The mass of the bumper cars and the velocity
Explain why after the bumper cars crash into each other they stop
Total momentum is zero after the collision as the momentum before the collision was also zero. the momentum of each car before the collision was equal and opposite. And momentum is conserved
Give two ways the direction of force on a wire can be reversed
By changing the direction of current and reversing the direction of the magnetic field
Explain why coil rotate when there is a current in a coil in a simple motor
The current in a wire in the wire causes a magnetic field to be produced.
The current is in opposite directions in each side of the coil therefore the force act in opposite directions on either side of the coil this causes the coil to rotate
The current on each side is the same direction
Explain what properties of a spring in a mattress will make the mattress soft
The springs have a low spring constant as they can compress by a larger amounts
An aeroplane has a lift force (upwards) weight force (down) and air resistant and thrust force ( forwards force) when it is flying at constant speed which are equal.
Explain how the forces should change from equal to the aeroplane can land
Thrust should decrease so there is a resultant force in the opposite direction of flying.
And lift force should decrease so that there is a larger weight force creating a downwards resultant force
Explain why light refracts as it passes from air into glass
The speed in glass of the wave is lower so the edge of the wave front entering the glass would slow down however the rest of the wave body would still travel at A higher speeds in air therefore causing a change in direction
Play what would happen if a paperclip was moved removed from the south pole of a magnet to the north pole
The paper clip will still be attracted to the North Pole because of induced magnetism
What 2 properties should be the same for each spring in a keyboard
The spring constant and lengths of spring
What happens to a spring that is stretched beyond its limit of proportionality
It will be iinelastically deformed
Explain why a bowling ball will decelerate as it travels along the bowling lane
As the ball accelerates air resistance increases until it is equal and there for work is done on the ball
Explain why x rays produce images insid the body
They can penetrate through flesh and is absorbed by bones
Explain why a radiographer would stand behind a protective screen when taking images
Taking lots of X-rays will give a high dosage of X-rays which will increase the risk of cancer so the screen will absorb some of the rays
How are electrical signals in the transmitter produces a signal in the recieve era in a house
Electrical current in the transmitter produces radio waves which are absorbed by the recieve Ed inducing electrical current at the same frequancy in the recieve Ed
What is the advantage of the reduced speed limit on the roads
Decreased speed decreases stopping distance and therefore decreasing collisions
Explain why an empty van will have a shorter stopping distance than a loaded van
The same maximum
force is applied by the brakes
as less mass means the deceleration is greater so the breaking distance is shorter
A circuit is attached to a balance
When the circuit switch is closed the redaing on the balance increases . Why does this show an upwards force on the wire in the circuit .
The downwards force on the balance increases so the wire must experience an equal and opposite force
What is meant by elastic ally deformed
The spring will return to its original length after being deformed
The speed of a wave is affected by the depth of the water in a ripple tank.
The deeper the water the faster the wave
Explain how the depth of the water affect the wavelength of the wave if the frequancy is constant
Deeper water equals longer wavelength as speed increases and frequancy is constant
Why is an em used instead of a permanent magnet to separate steel from non magnetic materials
Em is easy to demagnetise so it is easy to remove the separated metal
Name 2 metal other than iron and steel that are attracted to the em magnet
Cobalt
Nickel
How doe infrared cameras show parts of the hand at diff temp
Diff temp of hand emits diff intensities of infrared radiation which are represented as diff colours on the camera surfaces
Tungesten has the highest melting point of all metals explain why it is used in X-ray machines.
It makes the machine more powerful
As some of the energy of the el e tronos cause heating therefore increasing the temp
However tungesten allows more electrons to collide per second compared to any other metal
An aeroplane accelerates from a low speed to high with the engine at max power.
Explain why acc is not constant
At max power the forward forc of engine is constant therefore as it accelerates the air resistance increases.
And resultant force = force from engine - air resistance
Therefore resultant force decreases
And acc is directly prop to resultant force so acc is not constant
What is weight
The force acting on an object due to gravity
What is the weight of an object depend on
The gravitational field strength at the point where the object is
What is the weight of an object directly proportional to you
The mass of an object
How is weight remeasured
A newton meter
When is work done on an object
When a force causes an object to move through a distance
What is velocity
Speed in a given direction
What is Newton‘s first law
If the resultant force acting on an object 80 the object will either remain stationary or if it is moving it will continue to move at the same speed in same direction
What is newton second law
The acceleration of an object is proportional to the resultant of force acting on an object
What is the acceleration of an object inversely proportional to you according to Newton‘s second law
The mass of the object
What is Newton’s third law
When two objects interact they exert equal and opposite forces on each other
What do peoples reaction time vary from
0.2 and 0.9
What is the amplitude of a wave
The maximum displacement of a point on a wave away from its undisturbed positioning
What are electromagnetic waves
They are transverse waves transfer energy from the source of the waves to and absorber
How are radio waves produced
Oscillations in electrical circuits
What happens when radio waves are absorbed
They create an alternating current with the same frequency as the wave itself
How are electromagnetic waves generated
Changes in atoms and the nuclei of atoms
What is radiation. dose
It is a measure of the risk of harm from an exposure of radiation of the body
What is radiation measured in
Sieverts
What is visible light used for
Fibre optic communications
What are the poles of a magnet
Places where the magnetic forces are strongest for the magnet
What does the strength of a magnetic field depend on on a magnet
The distance from the magnet
Explain the motor Effect
When a conductor such as the wire is carrying current and is placed in a magnetic field that is produced by a magnet the magnet and the wire will exert a force on each other
What is magnetic flux density measured in
In teslas T
A toy crane uses an electromagnet to pick up and move metal blocks explain how it is able to do that
By completing the circuit the electromagnet turns on. And current flows through the coil therefore a magnetic field is produced around the coil and therefore the iron core becomes magnetised.
When you move the electromagnet close to the blocks the blocks will be attracted to it switching off the current will switch off the electromagnet releasing the block
Explain how radio waves reaching a car aerial would produce signals in the electric circuit of the car radio
The car aerial will absorb the radio waves the electrons will vibrate therefore creating an alternating current with the same frequency at the radio eight
A man is swimming force A is the forward force and force be is the backwards force what happens to force b. When force a increases
The resultant forward force would be greater therefore it will cause demand to accelerate however as the forward force increases the force be also increases until it is equal and he will no longer accelerate. However he was still moving at a constant velocity which is higher
