Ohms Law

Question 1

How do you calculate the unknown electrical quantity when given two of the fundamental values of electricity?

Answer 1

V=I*R

Question 2

How do you calculate electricity in an circuit?

Answer 2

Energy=Power*Time

Power=Voltage*Current

Question 3

What Law is used to figure out the relationship between Power, Voltage, and Current?

Answer 3

Watt’s Law

Question 4

The Difference between Ohm’s Law and Watt’s Law?

Answer 4

Ohm’s Law states the relationship between voltage, current and resistance. Watt’s law states the relationship between power, voltage and current.

Question 5

How many Electrical Prefixes are there?

Answer 5

There is 10.

Question 6

Can You Name all of the Electrical Prefixes?

Answer 6

Terra, Giga, Mega, kilo, none, centri, milli, micro, nano, pico

Question 7

What are the symbols for each prefix?

Answer 7

T,G,M,k,none,c,m,u,n,p

Question 8

How do you convert from one prefix to the other?

Answer 8

Multiply or divide by the difference between the two values.

Question 9

What is the minimum and maximum value of resistance in a electrical unit?

Answer 9

Resistance can be lower that 0.01R or higher than 1,000,000R.

Question 10

What is Wh? and what are the most common forms of it?

Answer 10

Wh is the Watt-Hour, The amount of electrical energy consumed by a circuit over a period of time. The Most common way it is used is Wh (watt-hours), kWh (Kilowatt-hour), which is 1,000 watt-hours or MWh (Megawatt-hour) which is 1,000,000 watt-hours.

Question 11

What is dB and how is it expressed?

Answer 11

dB is The Decibel, The decibel is a one tenth unit of the Bel (symbol B) and is used to represent gain either in voltage, current, or power. It is a logarithmic unit expressed in dB and is commonly used to represent the ratio of input to output in amplifier, audio circuits or loudspeaker systems.

Question 12

What is an example of dB ratio of an input and output voltage?

Answer 12

dB ratio of an input voltage (Vin) to an output voltage (Vout) is expressed as 20log10 (Vout/Vin).

Question 13

Is the dB value positive or negative?

Answer 13

The value in dB can be either positive 920dB) representing gain or negative 9-20dB) representing loss with unity, ie input=output expressed as 0dB.

Question 14

What is the Phase Angle?

Answer 14

The difference in degrees between the voltage waveform and the current waveform having the same periodic time. It is a time difference or time shift and depending upon the circuit element can have a “leading” or “lagging” value. The phase angle of a waveform is measured in degrees or radius.

Question 15

What is Angular Frequency?

Answer 15

Another unit which is mainly used in a.c circuits to represent the Phasor Relationship between two or more waveforms is called Angular frequency 2pif with units in radians per second, rads/s.

Question 16

What is time constant?

Answer 16

Time constant of an impedance circuit or linear first-order system is the time it takes for the output to reach 63.7% of its maximum or minimum output value when subjected to a Step Response input. It is a measure of reaction time.

Question 17

How do you calculate Voltage? and What is its Measuring unit and Symbol?

Answer 17

V=I*R

Measuring unit is Volt, Symbol V or E

Question 18

How do you calculate Current? and What is its Measuring unit and Symbol?

Answer 18

I=V/R

Measuring unit is Ampere, Symbol I or i

Question 19

How do you calculate Resistance? and What is its Measuring unit and Symbol?

Answer 19

R=V/I

Measuring unit is Ohm, Symbol R or

Question 20

How do you calculate Conductance? and What is its Measuring unit and Symbol?

Answer 20

G=1/R

Measuring unit is Siemen, Symbol G or

Question 21

How do you calculate Capacitance? and What is its Measuring unit and Symbol?

Answer 21

C=Q/V

Measuring unit is Farad, Symbol C

Question 22

How do you calculate Charge? and What is its Measuring units and Symbol?

Answer 22

Q=C*V

Measuring unit is Coulomb, Symbol Q

Question 23

How do you calculate Inductance? and What is its Measuring units and Symbol?

Answer 23

VL=-L(di/dt)

Measuring unit is Henry , Symbol L or H

Question 24

How do you calculate Power? and What is its Measuring unit and Symbol?

Answer 24

P=V*I

Measuring unit is Watts, Symbol is W

Question 25

How do you calculate Impedance? and What is its Measuring units and Symbol?

Answer 25

Z^2=R^2+X^2

Measuring unit is Ohm, Symbol is Z

Question 26

How do you calculate Frequency? and What is its Measuring units and Symbol?

Answer 26

f=1/T

Measuring unit is Hertz, Symbol is Hz

Question 27

What is this equation trying to find: R=V/I?

Answer 27

With given parameters Voltage & Current you will find the Resistance

Question 28

With given parameter Power and Resistance how would you calculate to get Voltage (V)?

Answer 28

V=square root P*R

Question 29

With given Parameter Voltage and Resistance how would you calculate to get the Power(P)?

Answer 29

P=V^2

R

Question 30

Find the voltage applied across an unknown resistor which dissipates 20 watts power while 5 A current is flowing through it.

Answer 30

V=20 watts / 5 A= 4V

Question 31

Electric Current is measured in the unit of the ampere, or amp. What is the physical definition for this unit? What fundamental quantities constitute 1 ampere of electric current?

Answer 31

1 ampere of electric current is the rate of electron motion equal to 1 coulomb per second: I=Q
t
Where, I= Electric current (amperes)
Q= Charge in motion (coulombs)
t= Time (seconds)