Paper 1 final notes Flashcards

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1
Q

How does a loudspeaker work

A

a.c. power supply provides the wire with a current that is always changing direction

-the magnetic field interacts with the current in the coil exerting a force

-the magnetic field is alternating causing the force to change direction back and forth

-the paper cone vibrates and a longitudinal sound wave is formed.

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2
Q

What is the distribution of the current and the voltage in a series circuit?

A

The current is the same throughout and the voltage splits across components

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3
Q

What is the distribution of the current and the voltage in a parallel circuit?

A

The current splits throughout components and the voltage stays the same.

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4
Q

How does an earth wire act as a safety feature?

A

-The earth wire is connected to the metal casing
-The earth wire provides a low resistance route to the earth
-The earth wire has a fuse connected to it that melts and breaks the circuit when the current is too high.

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5
Q

Define a.c.

A

Current that is continuously changing direction

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6
Q

Define d.c.

A

Current that only travels in one direction

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7
Q

What is a circuit breaker

A

A device that stops any current from flowing when the current is too high.

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8
Q

Do Filament Lamps and Diodes obey Ohms law

A

No they don’t as current isn’t proportional to voltage.

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9
Q

What is the relationship between light and resistance in a Light resistor

A

As light increases resistance decreases

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10
Q

What is the relationship between temperature and resistance in a thermistor

A

As temperature increases the resistance decreases

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11
Q

Why does resistance increase as the temperature of the filament increases?

A

Because the positive ions vibrate more inhibiting the flow of electrons.

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12
Q

What is a fuse?

A

A safety device that melts and breaks the circuit when the current is too high

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13
Q

What colour are earth, live and neutral wires

A

Earth wires are green and yellow
Neutral wires are blue
Live wires are brown

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14
Q

What is double insulation

A

When the wires inside a device and the outer case of the device are insulated - there is no chance of electrocution.

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15
Q

What are the EM waves starting from the largest wavelength

A

Radio
Microwaves
Infrared
Visible light
UV light
X-rays
Gamma rays

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16
Q

What are the uses of EM waves

A

Radiowaves: communication
Microwaves: Heating food
IR: Cooking
Visible light: Viewing objects and photography and communication
UV light: Fluorescent lamps and markings
X-rays: Viewing the internal structure of objects
Gamma rays: Kills cancer cells

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17
Q

Harm caused by EM waves:

A

IR: Can damage surface cells due to skin burn
UV: can cause skin cancer
Gamma: can cause cell mutations if exposed for too long.

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18
Q

How to prevent harm from EM waves

A

-Wear suncream and sunglasses for UV
-Limit exposure time to X-ray and stand behind a lead screen
-Limit exposure time to Gamma

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19
Q

Similarities of EM waves

A

-They are all transverse
-They all transfer energy
-They can all be reflected, refracted
-They all move at the same speed in free space.

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20
Q

How to make X-rays

A

X-rays are made when high-speed electrons are stopped

21
Q

How to make Gamma

A

Gamma rays are emitted from unstable nuclei

22
Q

What is a hard magnetic material?

A

Something that is difficult to magnetise and difficult to demagnetise

23
Q

What is a magnetic field

A

The area between magnets where magnetism can be detected

24
Q

What are magnetic field lines

A

Lines that present the direction of the magnetic field.

25
Q

How to increase the magnetic field strength of an electromagnet

A

-Increase the current
-Turn the wire into a coil

26
Q

How to increase the magnetic field strength of a coil

A

Increase the number of turns on the coil
Increase the current

27
Q

What is a motor

A

A wire that spins

28
Q

How is the motor effect created

A

Two permanent magnets have a current carrying wire inbetween them.

-The two magnetic fields interact exerting a force on the wire causing it to spin

29
Q

Fingers for Flemming’s Left hand rule?

A

Thumb = force
First Finger = Field
Second Finger = Current

30
Q

What is the definition of specific heat capacity

A

The amount of energy needed to heat 1kg of an object by 1 degree.

31
Q

How does a motor spin?

A

The current carrying wire experiences a temporary magnetic field

This magnetic field interacts with the magnetic field of the permanent magnets

-A force is exerted on the wire causing it to spin.

32
Q

What is the role of brushes

A

-Conducts current between stationary wires and rotating wire of motor.

33
Q

Roles of commutators

A

-Reverses the current every half turn to ensure the motor continues turning.

34
Q

What is a galaxy

A

A galaxy is a collection of billions of stars

35
Q

What is a universe

A

A universe is made up of billions of galaxies

36
Q

What does gravitational pull maintain in space

A

-It keeps planets orbiting stars
-It keeps comets orbiting stars
-Keeps the moon orbiting planets
-Keeps satellites orbiting planets

37
Q

What is a satellite

A

An object that orbits a planet

38
Q

What does the strength of gravitational pull on a planet depend on

A

The mass of the planet
The distance between the planet and the sun

39
Q

At what point of a comet’s orbit does it move fastest

A

-Closest to the sun as the gravitational pull is greatest here

40
Q

Life cycle of a star similar to the sun

A

Nebula
Main sequence
Red Giant
White dwarf
Black dwarf

41
Q

How does nebula become main sequence

A

Gravitational pull allows hydrogen nuclei to get closer for fusion to occur

42
Q

How does main sequence become a red giant/red supergiant

A

The main sequence runs out of hydrogen fuel and burns helium instead causing it to expand

43
Q

How does Red giant become white dwarf

A

The star shrinks

44
Q

How does white dwarf become black dwarf

A

The star cools

45
Q

Life cycle of a very high mass star

A

Nebula
Main sequence
Red supergiant
Supernova
Neutron star/black hole.

46
Q

How does a red supergiant become a supernova

A

A huge explosion

47
Q

What colour are very hot stars

A

Blue

48
Q

What colour are cooler stars

A

Red

49
Q

What is absolute magnitude

A

How the brightness of a star appears from a fixed distance