The paper 2 deck OMG Flashcards
What does the wavelength and intensity of infrared radiation depend on
The temperature of the object a hotter object will create a shorter wavelength and have a higher intensity.
What does a perfect black body do to radiation
It absorbs all of it no radiation is reflected and no radiation is transmitted (passed through)
This means that a perfect black body is also the best possible emitter of radiation
What does an object that absorbs radiation well also do
It will also emit radiation well
What will it object to if it is warmer than its surroundings
It will emit more radiation that it absorbs, decreasing its temperature. The Reverse is also true
what does it Mean if an object is at a constant temperature
It means the object is absorbing radiation at the same rate as it is emitting radiation
Cloud cover can affect how much energy is radius from the Earth explain why
The clouds can reflect infrared light back to the Earth and then prevent it from being radiated into space
What is specular reflection
When all the light rays reflect in the same direction on a smooth surface producing an image
What is diffuse reflection
When light rays but have scattered after reflecting off of a rough surface which does not produce an image
What are all the colours in the spectrum of visible light
Red orange yellow green blue Indigo Violet
How do coloured filters work
They walk by absorbing specific wavelength and transmitting other wavelengths
Why can a direct current not work in transformers
They produce a constant magnetic field and therefore it does not work in transformers
What colour will the green object appear if any coloured filter is used on light and at least one colour goes through
It will appear black unless the colour is shining through a green filter.
What do transformers only work with
Transformers only worked with alternating-current this because we need a changing magnetic field to induce a potential difference
Is the potential difference in the primary coil the same as in the secondary coil if the secondary coil has the same number of turns
Yes
What happened to the potential difference in a primary coil if the secondary coil has double its turns
The potential difference is doubled- therefore this is a step up transformer
What are the four magnetic metals
Iron steel cobalt and nickel
How do you plot the magnetic field of a bar magnet using a compass
You place the south end of the compass next to the north end of the bar magnet and place An x onto where the North Pole is pointing to then repeat this with the South Pole on this point and plot across where the North Pole arrow is pointing now and connect all the points with a line.
What is a solenoid
A solenoid consists of a wire coiled up into a spiral shape.
What is an electromagnet
An electromagnet is a solenoid wrapped around an iron core
How do we turn high voltage appliances on and off
We use a relay
What is a relay
A relay is a low voltage circuit using an electromagnet that is turned on and off using switch controlling a high voltage circuit using Magnetism to attract an iron block which puts two contacts on top of each other and allows current to flow through the high voltage circuit
What is the motor effect
A wire carrying a current creates a magnetic field. This can interact with another magnetic field, causing a force that pushes the wire at right angles. This is called the motor effect
What does a split ring commutator do to a circuit
It rotates it
What happens if we move a wire up through a magnetic field.- this is the generator effect
Is there a potential difference is induced across the ends of the wire same goes for current.
The induced potential difference in current are larger if we use a stronger magnetic field we move the wire more rapidly and if we shape the wire into a coil the more turns on the coil the greater the induced pot diff and current
How does a moving coil loudspeaker work
First we have a cone which has a coil of wire wrapped around one end which is connected to an AC electrical supply. We also have a permanent magnet which goes through the coil of wire. As the current passes through the coil it generates a magnetic field. The magnetic field from the coil now interacts with the magnetic field from the permanent magnet. These magnetic fields either attract or repel each other. This produces a resultant force which causes the cone to move.
When the current switches direction the direction of the force of the cone reverses. This causes the cone to move in and out generating sound waves. By changing the frequency of the AC supply we can change the frequency that the cone vibrates. A high frequency produces a high-pitched sound and the reverse is also true. If we increase the size of the current then we increase the amplitude of the vibration. This increases the volume of the sound.
What happens to the current the direction of movement changes
The direction of the current changes, this also occurs if we switch the polls of a magnet going into the solenoid
What is an alternator
A coil of wire rotating and a magnetic field
When is the maximum potential difference of an alternator
When it is horizontally inside the magnetic field
How do moving coil microphones work
In a moving-coil microphone:
pressure variations in sound waves cause the flexible diaphragm to vibrate
the vibrations of the diaphragm cause vibrations in the coil
the coil moves relative to a permanent magnet, so a
potential difference
is induced in the coil
the coil is part of a complete circuit, so the induced potential difference causes a current to flow around the circuit
the changing size and direction of the induced current matches the vibrations of the coil
the electrical signals generated match the pressure variations in the sound waves
https://www.bbc.co.uk/bitesize/guides/z8c7pbk/revision/4
What is a galaxy
A large group of stars and a nice chocolate bar
How are stars formed
All stars begin life in the same way. A cloud of dust and gas, also known as a
nebula
, becomes a protostar, which goes on to become a
main sequence
star. Following this, stars develop in different ways depending on their size.
Stars that are a similar size to the Sun follow the path:
red giant star
white dwarf
black dwarf
Stars that are far greater in mass than the Sun follow the path:
red super giant star
supernova
neutron star, or a black hole (depending on size)
