Electricity, light & waves, transformers EQTs

Question 1

Time, current, charge

Answer 1

Charge= current x time
Q= I x t
C = A x s

Question 2

Elctrical energy transfered, EMF, charge

Answer 2

Emf = electrical energy transferred / charge
V = E x I
V = J x C

Question 3

energy transeferred, p.d., charge

Answer 3

P.d. = energy transferred / charge
V = E / Q
V = J / C

Question 4

Energy, p.d., time

Answer 4

P.d. = Energy / time
V = E / t
V = J / s

Question 5

P.d., resistance, current

Answer 5

Resistance = p.d. / current
R = V / I
Ohms = V / A

Question 6

Current, p.d., power

Answer 6

Power = p.d x current
P = V x I
W = V x A

Question 7

Time, electrical energy, p.d., current

Answer 7

Electrical energy = current x p.d. x time
E = I x V x t
J = A x V x s

Question 8

Resistors in series

Answer 8

Rt = R1 + R2 …..

Question 9

Resistors in parallel

Answer 9

1/Rt = 1/R1 + 1/R2 …..

Question 10

Frequency, speed, wavelength

Answer 10

Speed = wavelength x frequency
m/s = m x Hz

Question 11

Angle of incidence and refraction

Answer 11

Angle of incidence (i) = angle of refreaction (r)

Question 12

Refractive index

Answer 12

Speed of light in air / speed of light in substance

OR

n = sin (i) / sin (r)

Question 13

Critical angle

Answer 13

n = 1 / sin C

OR

sin C = 1/ n

Question 14

Wave speed

Answer 14

Frequency (Hz) x wavelength (m)

Question 15

Voltage in a transformer

Answer 15

V1 / V2 = N1 / N2

v= voltage
n= n. turns
1= primary coil
2= secondary coil

Question 16

Power in a transformer

Answer 16

V1 x I1 = V2 x I 2

v= voltage
I= current
1= primary coil
2= secondary coil