formulas

Question 1

velocity

Answer 1

displacement/time taken

Question 2

acceleration

Answer 2

change in velocity/time taken

Question 3

uniform acceleration

Answer 3

v-u/t in secs

Question 4

displacement

Answer 4

1/2 (u+v) t

Question 5

average velocity

Answer 5

1/2 (u+v)

Question 6

pressure (N/m^2 or Pa)

Answer 6

force (Fn)/ area (Am^2)

Question 7

mass (kg)

Answer 7

density x volume

Question 8

weight (N)

Answer 8

mass (kg x m/s^2 or kg x N/kg) x gravity

Question 9

pressure in liquid (Pa or N/m^2)

Answer 9

hpg (depth beneath surface x pressure in kg/m^3 x gravitational field strength (10 on earth) )

Question 10

F1/A1 = F2/A2

Answer 10

F1 x D1 = F2 x D2

Question 11

density (kg/m^3)

Answer 11

mass (kg)/ volume(m^3)

Question 12

moment

Answer 12

Fd (Force in N x Perpendicular distance in m)

Question 13

efficiency

Answer 13

useful energy output/ total energy input x 100%

Question 14

work done (J)

Answer 14

Fs (constant force in N x distance moved in direction of force in m)

Question 15

kinetic energy (J)

Answer 15

1/2 mv^2 (mass in kg x speed in m/s)

Question 16

gravitational potential energy (J)

Answer 16

mgh (mass in kg x gravitation field strength in N/kg or m/s^2 x height in m)

Question 17

sini/sinr

Answer 17

constant

Question 18

n (refractive index)

Answer 18

c/v (speed of light in vacuum/ speed in light in medium)

Question 19

n (refractive index)

Answer 19

sini/sinr (angle of incidence in vacuum/angle of incidence in medium)

Question 20

sinc (critical angle of medium)

Answer 20

1/n (1/refractive index of medium)

Question 21

f (frequency in Hz)

Answer 21

1/T (1/period in s)

Question 22

v (speed of wave in m/s)

Answer 22

wavelength (m)/ period (s)

frequency (Hz) x wavelength (m)

Question 23

period

Answer 23

time taken/ no. of waves

Question 24

I (current in A)

Answer 24

Q (charge in c)/ T (time in s)

Question 25

E (e.m.f. of electrical energy source in V)

Answer 25

W (work done in J)/ Q (amt. of charge in c)

Question 26

V (p.d. in V)

Answer 26

W (work done in J)/ Q (amount of charge in C)

Question 27

R (resistance in ohm)

Answer 27

V ( p.d in V)/ I (current in A)

Question 28

R (resistance)

Answer 28

pL (resistivity x length)/ A (cross-sectional area)

Question 29

P (resistivity in ohm x m)

Answer 29

RA (resistance in ohm x cross-sectional area in m^2)/ l (length in m)

Question 30

I1=I2=I3

Answer 30

series current all the same

Question 31

Ve=V1+V2

Answer 31

potential difference across series circuit = sum of p.d.

Question 32

I=I1+I2

Answer 32

sum of individual current = main current

Question 33

Ve=V1=V2

Answer 33

p.d. across parallel circuit all the same

Question 34

R=R1+R2+….+R3

Answer 34

series resistance = sum of all resistance

Question 35

1/R=1/R1+1/R2+….+1/Rn

Answer 35

parallel circuits resistance = sum of reciprocal of effective resistance

Question 36

P ( power in W)

Answer 36

VI (p.d. in V x electric current in A)
V^2/R (p.d square/resistance in ohm)
I^2 x R (current square x resistance)

Question 37

E (energy in J)

Answer 37

Pt (power in W x time in s)
VIt (p.d. in V x current In A x time in s)
V^2t/R (current in A square x time in s/resistance in ohm)
I^2Rt (current square x resistance in ohm x time in s)

Question 38

1kWh

Answer 38

3.6 x 10^6

Question 39

cost of electricity consumption

Answer 39

no. of consumed kWh x cost per kWh

Question 40

energy

Answer 40

Pt (power x time)