Physics Exam S2 February 2024 Flashcards
What happens when light hits a mirror?
It gets reflected.
How are angles measured?
From the normal to the ray,
What is the law of reflection?
The angle of incidence is equal to the angle of reflection. (i=r)
List the types of mirrors.
Plane (Flat)
Convex (Curved Outwards)
Concave (Curved Inwards)
What are some uses of plane mirrors?
Used in Vanity Mirrors
Used in periscopes in submarines
Used in kaleidoscopes to make shape patterns
What are some uses of concave mirrors?
Make objects appear larger
Used in dentist mirrors
Used in shaving mirrors
What are some uses of convex mirrors?
Used in rear mirrors. They make objects appear farther.
Used in space telescopes.
What are the three primary colours of light?
Red
Green
Blue
What are the three secondary colours of light?
Yellow (Red and Green)
Magenta (Blue and Red)
Cyan (Green and Blue)
What colours make up white (visible) light?
ROYGBIV
What colours are most and least refracted?
Most - violet
Least - Red
What is refraction?
When light changes speed when it passes from one material to another. Sometimes there is also a change in direction.
What is the normal?
A dashed line that is drawn 90 degrees to the surface of the object.
What is the angle of incidence? (i)
The angle measured between the incident ray and the normal.
What is the refracted ray?
The ray of light that comes out the other side of the object.
What is the angle of refraction (r)
The angle measured between the refracted ray and the normal.
What is the shape of a concave lens?
Thin in the middle, thick at the edges.
What is the shape of a convex lens?
Thick in the middle, thin at the edges.
What happens when light refracts through a concave lens?
Concave lenses cause light to spread out (diverge).
What happens when light refracts through a convex lens?
Convex lenses cause light to come to a focus (converge)
How does the thickness of the lens affect the refraction of the lens?
The thicker the lens, the greater the refraction so the more the light bends.
What are some uses of concave lenses?
Shortsighted glasses - to help you see far away
What are some uses of convex lenses?
Magnifying glass- used to make objects appear bigger
Microscope - magnify the object
Longsighted glasses - to help you see things up close
Light is a wave.
:)
What do waves transfer?
Energy
What are the 7 waves on the electromagnetic spectrum?
Red Monkeys mnemonic
What happens to the wavelength when the frequency decreases?
The wavelength increases.
What is the speed of light?
300 million m/s. All waves on the spectrum travel at this speed.
What are some uses and hazards of Radio Waves?
Used for mobile phone and satellite communications.
No serious hazards.
What are some uses and hazards of Microwaves?
Used for heating food.
Can cause mild heating effects.
What are some uses and hazards of Infrared waves?
Thermal imaging and TV Remotes
Burns skin
What can forces change?
The speed, shape and direction of an object.
What are the different types of contact forces?
Push, Pull and Twist. (the bop-it forces)
What are some examples of contact forces?
Opening a door, turning a tap, friction.
What are some examples of non-contact forces?
Static electricity, gravity, magnetism.
What device is used to measure forces?
A Newton meter.
What is friction?
The force produced when two objects rub against each other.
What effects does friction have on the motion of an object?
Friction always slows a moving object down. It acts in the opposite direction to an object’s motion.
What is produced when objects rub against each other?
Heat energy.
Where would friction be useful?
Your feet would slide when you move.
Car and bike brakes would not work.
Clothes would slip through pegs on a washing line.
What are some ways to decrease friction?
Using a lubricant - e.g. oil in a car engine.
Streamlining an object’s shape - can also help with air resistance.
Where would friction not be useful?
Moving parts in a car engine get too hot if friction is too high, stopping the engine.
The bike chain and gear wheels are affected by friction, making riding the bike harder.
How is air resistance produced?
Air resistance occurs when air moves over an object. Fiction acts when the object collides with particles of air. The friction produced by the air is called air resistance/drag.
How does the area of the parachute affect the time it takes to fall to the ground?
The greater the area of the parachute, the more time it takes to fall to the ground.
What are balanced forces?
When the forces acting on an object are the same size but opposite in direction.
What are unbalanced forces?
When the forces acting on an object are different sizes but opposite in direction.
What is upthrust?
The upward force on an object provided by a liquid or gas.
Why do objects float?
The upthrust balances the object’s weight.
What is meant by the speed of an object?
The measure of how far it travels each second.
What are the units for speed?
metres per second (m/s)
What are electrons?
Electrons are tiny, negatively charged particles.
What is static electicity?
It is when you have a build up of electrons on an object. Once they are on the object, they do not flow, (hence STATIC electricity)
What is current and what are its units?
The flow of electrons in a circuit. Measured in Amps (A)
Why do we use circuit diagrams rather than drawings or photos?
It is easier and quicker + you don’t need to be a skilled artist
The same symbols are used all over the world regardless of language
What is voltage, and what are its units?
The energy given to the charges (electrons) in a circuit.
Measured in Volts (V)
What is resistance, and what are its units?
The opposition to current flow in a circuit.
Measured in Ohms (Ω)
What is the direction of current flow in a simple circuit?
Negative to positive (short line to longer line)
What happens when a battery is the wrong way round in a circuit?
They push the electrons from both directions. This means the electrons cancel each other out, therefore current does not flow.
What are conductors and insulators?
Conductors allow electrical current to flow through them.
Insulators do not.
What are the causes of electrical hazards?
Danger of electrocution/fire.
How does adding more bulbs in a circuit affect the brightness?
Series - It decreases
Parallel - It stays the same
What are some advantages of a series circuit?
Cheaper then parallel circuits (less wire)
Easier to build
What are some disadvantages of a series circuit?
When one component goes out, the others go out too.
What device is used to measure current?
Ammeter
What is the Circuit Rule for the current of a series?
The current is the same at all points.
What is the Circuit Rule for the voltage of a series?
The voltages across the devices (bulbs) add up to give the battery voltage.
What is the Circuit Rule for the current of a parallel?
The current passing through the battery splits up at each branch.
What is the formula for calculating speed?
V=d/t
What are some uses and hazards of light waves?
Seeing
Strong light can cause damage to vision
What are some uses and hazards of UV waves?
Sunbeds + Security marking
Skin cancer
What are some uses and hazards of X-rays?
Taking images of the skeleton
Can cause mutations in cells
What are some uses and hazards of Gamma rays?
Treating cancer
Causing cancer
