exams igcse

moles of solid

mass/Ar

moles of liquid

concentration x volume

Average speed

distance/time (ms-1)

Average velocity

displacement/time (ms-1)

Acceleration

(final displacement - intial displacement)/time

weight

mass (kg) x gravitational field strength (N)

Force

mass (kg) x acceleration

Density

mass (kg)/volume

hooks law

force (N) = constant x extension (m)

pressure

pressure(Pa)= force/area

fluid pressure

density (Kgm-3) × gravitational field strength (ms-2 or Nkg-1) × height (m)

Work

= force (N) × distance moved (m)

power

work(j)/time(s)

Gravitational potential energy (J)

= mass (kg) × gravitational field strength (ms-2 or Nkg-1) × height (m)

Efficiency (%)

useful output/total output x 100

moment(Nm)

Force x perpendicular distance from piviot

currrent

charge/time

voltage 1

energy trannsfered(J)/charge(C)

Voltage (V) 2

= current (A) × resistance (Ω)

Power (W) 1

current (A) × voltage (V)

Power (W) 2

current^2 (A) × resistance (Ω)

Energy transferred (J) 2

= current (A) × voltage (V) × time (s)

Energy transferred (J)

power (W) × time (s)

Resistors in series

Total Resistance (Ω) = sum of individual resistors (Ω)

Resistors in parallel:

1/R +1/R + 1/R….

Transformer 1

voltage in secondary coil (V) = turns on secondary coil voltage in primary coil (V) turns on primary coil

Transformer 2

voltage in primary coil (V) = current in secondary coil (A) voltage in secondary coil (V) current in primary coil (A)

Wave speed (ms-1)

frequency (Hz) × wavelength (m)

frequencey (Hz)

1/ Period (s)

Refractive index 1

sine of the angle of incidence/i sine of the angle of refraction, r

Refractive index 2

= speed of light in vacuum /speed of light in material

Refractive index 3

1/ sine of critical angle

Radioactive alpha decay

4H2

Radioactive beta decay:

0e-1