A1 LT8

Question 1

What will happen to current if the applied voltage is decreased to half of its previous value?

Answer 1

Current will also decrease to half of its previous value.

Question 2

What is the modified version of scientific notation used in the electrical trade?

Answer 2

Engineering notation

Question 3

To multiply a number by 10^3 in scientific notation, how do you move the decimal point?

Answer 3

Three places to the right

Question 4

How can the relationship between power, voltage, and current be stated mathematically?

Answer 4

Power is directly proportional to the square of the voltage and current.

Question 5

What is the main way to solve electrical circuit problems?

Answer 5

By applying Ohm’s and Watt’s laws

Question 6

What does inversely proportional mean in terms of resistance and current?

Answer 6

If the resistance is doubled, the current will decrease to half of its previous value.

Question 7

In engineering notation, what kind of exponents are used with powers of 10?

Answer 7

Multiples of three

Question 8

How do you express 0.057 mA in terms of A?

Answer 8

57 ?A

Question 9

What is power?

Answer 9

Rate of doing work or energy transfer

Question 10

What is the abbreviation for the power loss in conductors?

Answer 10

P = I^2 x R

Question 11

What does Watt’s law state?

Answer 11

Power in a circuit equals the product of the voltage and the current.

Question 12

What does the kilo represent?

Answer 12

10

Question 13

What is 5600 milliohms expressed in kilohms?

Answer 13

0.0056 k?

Question 14

What does voltage measure?

Answer 14

Amount of energy possessed by an electron

Question 15

What does PR loss refer to?

Answer 15

Power loss as I^2 x R

Question 16

What is Watt’s law?

Answer 16

P = E x I

Question 17

What is the formula provided for power?

Answer 17

P = 1R

Question 18

What is the resistance of a baseboard heater connected to a 240 V source producing heat at the rate of 1500 W?

Answer 18

38.4

Question 19

At what rate would heat be dissipated if a heater with the same resistance was connected to a 120 V source?

Answer 19

375 W

Question 20

What is one of the forms in which Ohm’s law can be expressed?

Answer 20

E=I x R

Question 21

How do you convert milliohms to kilohms?

Answer 21

Move the decimal point six places to the left

Question 22

What does horsepower refer to?

Answer 22

Amount of work the motor delivers on the shaft

Question 23

What is the efficiency of a motor?

Answer 23

Ratio of output watts to input watts at rated load

Question 24

What does motor efficiency represent?

Answer 24

How much of the input power is converted to useful output power

Question 25

For a 10 HP motor operating at 75% efficiency, how many input watts are drawn by the motor?

Answer 25

9947 watts input

Question 26

How to determine the HP a motor is delivering on the shaft if it is drawing 3730 watts at rated load?

Answer 26

5 HP

Question 27

What happens to the current in a circuit if the voltage doubles?

Answer 27

Current also doubles.

Question 28

What is the formula for voltage?

Answer 28

E=I x R

Question 29

What is the formula for resistance?

Answer 29

R=E/I

Question 30

What is the formula for current?

Answer 30

I=E/R

Question 31

How can Watt's law be transposed?

Answer 31

E=P/I

Question 32

How does the power change when voltage doubles in a circuit?

Answer 32

Power also doubles.

Question 33

What other form can Watt's law be transposed to?

Answer 33

P=E x I

Question 34

How can 25,000 volts be written in engineering notation?

Answer 34

25 kV

Question 35

What effect does increasing the rate of electron flow have on a resistive device?

Answer 35

It becomes warmer due to more collisions and energy transfer.

Question 36

What happens to the power if both the voltage and current double in a circuit?

Answer 36

Power increases by four times.

Question 37

How much current would a 200 W light bulb draw from the same 120 V source?

Answer 37

1.67 A

Question 38

What is the formula to calculate percent efficiency of a motor?

Answer 38

100% efficiency = (output power / input power) x 100

Question 39

How does power change with an increase in current?

Answer 39

Increases

Question 40

What is the value of power when resistance is 80 and current is 0.03?

Answer 40

= 192 W