All definitions Flashcards by Nader Edward

What is Density?

mass / volume OR mass per unit volume OR m/v (using symbols explained)

How well did you know this?

Not at all

Perfectly

What is Mass?

Amount of a matter inside the body OR property which resists change in motion.

How well did you know this?

Not at all

Perfectly

What is Weight?

Pull of gravity acting on an object.

How well did you know this?

Not at all

Perfectly

What is Deceleration?

Decrease in velocity / Slowing down.

How well did you know this?

Not at all

Perfectly

What is Centre of mass?

(The point in the body) where (all) the mass / weight / gravity acts.

How well did you know this?

Not at all

Perfectly

What is Moment of a force about a point?

force multiply perpendicular distance (of force) from the point.

How well did you know this?

Not at all

Perfectly

What is the Limit of proportionality?

(The point where) proportionality between force/weight and extension/Hooke’s Law stops.

How well did you know this?

Not at all

Perfectly

What is Hooke’s Law?

extension of spring proportional to Load/Force.

How well did you know this?

Not at all

Perfectly

What is Acceleration?

v – u/t OR ∆v/t (symbols used to be explained) OR change of velocity ÷ time OR rate of change of velocity OR change of velocity per second / in 1 sec.

How well did you know this?

Not at all

Perfectly

What is Power?

Work done per unit time OR Rate of doing work.

How well did you know this?

Not at all

Perfectly

What is Efficiency?

energy out/energy in or power out/power in.

How well did you know this?

Not at all

Perfectly

What is Pressure?

Force /Area OR Force per unit area OR F/A (using explained symbols).

How well did you know this?

Not at all

Perfectly

What is Renewable?

Continuously regenerated and not used up.

How well did you know this?

Not at all

Perfectly

What is the Law of conservation of energy?

Energy is neither created nor destroyed but can be changed from one type to another.

How well did you know this?

Not at all

Perfectly

What is the Law of conservation of momentum?

Sum of momenta before collision = sum of momenta after collision.

How well did you know this?

Not at all

Perfectly

What is Specific Heat capacity?

1Kg by 1
heat energy needed to raise temperature of
°C.

How well did you know this?

Not at all

Perfectly

What is Nuclear fusion?

nuclei join together to produce a different element (and energy).

How well did you know this?

Not at all

Perfectly

What is Absolute Zero?

minimum possible temperature , where is has least kinetic energy and speed.

How well did you know this?

Not at all

Perfectly

What is Nuclear fission?

is the splitting of a large atom into two or more smaller ones.

How well did you know this?

Not at all

Perfectly

What is Monochromatic?

has only one frequency / wavelength.

How well did you know this?

Not at all

Perfectly

What is Longitudinal?

Vibrations OR Oscillations of molecules in direction of travel (of wave).

How well did you know this?

Not at all

Perfectly

What is Transverse?

Vibrations OR Oscillations of molecules in direction of travel (of wave).

How well did you know this?

Not at all

Perfectly

What is Compression?

(Region) where air molecules are pushed together (closer) & air pressure is raised.

How well did you know this?

Not at all

Perfectly

What is Rarefaction?

(Region) where air molecules are pushed apart (further) & air pressure is reduced.

How well did you know this?

Not at all

Perfectly

What is a Virtual image?

not produced by real rays crossing OR cannot be caught on a screen OR rays appear to come from image/ rays diverge away from the image.

What is a Real image?

image can be formed on a screen OR is formed by rays of light meeting OR is formed on the opposite side of the lens from the object.

What is Focal length?

distance from (principal) focus/focal point to (the center of) the lens.

What is Critical angle?

The greatest angle of incidence at which refraction occurs. OR the angle of incidence at which the refracted ray travels along the boundary / angle of refraction is 90.

What is Ultra sound?

(a sound wave with a) frequency above the frequency audible by humans OR/ inaudible (to humans).

What is Total internal reflection?

Reflection in a more dense medium where there is no refracted ray OR All light in a more dense medium is reflected when angle of incidence > critical angle i=r.

What is the Focus point?

(Point on the principal axis where parallel rays meet after passing the lens.)

What is an Electric field?

(Region) where a force acts on a charge.

What is a Magnetic field?

(Region) where a force acts on a magnet.

What is Electromagnetic induction?

when magnetic field is cut by wire/coil/solenoid so a current/e.m.f caused.

What is a Transformer is 100% efficient?

very little energy/power lost or energy/power in = energy/power out.

What is Direction of an electric field?

direction of the force on a positive charge.

What is a Parallel connection?

Each appliance is connected across same V supply.

What is E.M.F?

energy supplied / work done (per unit charge) to drive charge round a (complete) circuit OR p.d. / voltage across battery.

What is Analogue and digital?

analogue; continuously increasing / decreasing readings. Digital; readings increase / decrease by one unit (idea of two states only).

What is Electromotive force of 12 V?

(Energy or work done) per unit charge where 12 J of energy are delivered for every coulomb of charge.

What is Direction of a magnetic field?

direction of the force on a North pole.

What is Ionizing?

electrons removed from/gained by the molecules.

What is Ionization of a gas molecule?

Atoms/molecules lose/gain electrons OR become charged.

What is Half-Life?

time taken for half the substance to decay.

What is the Nature of γ‑rays?

electromagnetic (waves/radiation /rays) OR high energy photons.

What is the Nature of an alpha particle?

2 protons and 2 neutrons OR helium nucleus.

What is Mass number (nucleon number)?

it is the sum of the protons and neutrons.

What is Atomic number?

it is total number of protons in the nucleus.

What are Isotopes?

They are different atoms of the same elements having same atomic number (Z) but different mass numbers (A).

What is Average orbital speed?

(from the equation) v = 2π r / T where r is the average radius of the orbit and T is the orbital period; recall and use this equation.

What is a Light year?

Distance travel by light in one year (365 day).

What is the Hubble constant (Hₒ)?

The ratio of the speed at which the galaxy is moving away from the Earth to its distance from the Earth; recall and use the equation H = v / d.

What is Speed?

Distance travelled per unit time.

What is Velocity?

Speed in a given direction.

What is Average speed?

Total distance travelled divided by total time taken.

What is Gravitational field strength?

g = W / m.

What is Spring constant?

k = F / x.

What is Force?

F = ma (force = mass × acceleration).

What is Momentum?

p = mv.

What is Impulse?

Impulse = F Δt = Δ(mv).

What is Resultant force?

F = Δp / Δt.

What is Work done?

W = F d = ΔE.

What is Kinetic energy?

Ek = ½ m v².

What is Gravitational potential energy change?

ΔEp = m g Δh.

What is Electric current?

I = Q / t.

What is Potential difference?

V = W / Q.

What is Resistance?

R = V / I.

What is Refractive index?

n = sin i / sin r; n = 1 / sin c.

What is the Normal and related angles?

Normal is a line perpendicular to a surface; angles of incidence, reflection, and refraction are measured from it.

What is the Transformer ratio?

Vp/Vs = Np/Ns.

What is Thermal radiation?

Thermal radiation is infrared radiation and all objects emit it.