Electrical quizes with answers review

7/30/2019 Electrical quizes with answers review

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Question 1

WHAT UNIT WILL THE TOTAL ENERGY STORED IN A CAPACITOR BE MEASURED IN ?

FARADS

JOULES

COULOMBS

VOLTS

Question 2

FOR MAXIMUM CAPACITANCE THE PLATES OF A CAPACITOR MUST BE AS BIG AS POSSIBLE

AS SMALL AS POSSIBLE

AS CLOSE AS POSSIBLE

AS FAR APART AS POSSIBLE

Question 3

INDUCTANCE IS MEASURED IN WHAT UNITS ?

AMPS PER SECOND

VOLTS PER METRE

COULOMBS

HENRIES

Question 4

IF A POLARISED (ELECTROLYTIC) CAPACITOR WAS CONNECTED THE WRONG WAY

ROUND TO A SUPPLY, WHAT WOULD HAPPEN ?

IT WOULD ONLY CHARGE UP DURING THE POSITIVE HALF CYCLE

IT WOULD ONLY CHARGE UP DURING THE NEGATIVE HALF CYCLE

IT WOULD NOT CHARGE UP AT ALL

IT WOULD BE DESTROYED

Question 5

CALCULATE THE ENERGY STORED IN A 200 MICRO FARAD CAPACITOR CONNECTED

TO A 200 VOLT SUPPLY

0.02 JOULES 8 JOULES

4 JOULES

40 JOULES

Question 6

IF 3 10 MICRO FARAD CAPACITORS ARE CONNECTED IN SERIES, THE CHARGE ON EACH

CAPACITOR WILL BE

THE SAME

3 TIMES AS GREAT

ONE THIRD

THREE TENTHSQuestion 8

WHAT IS THE FORMULA NEEDED TO CALCULATE THE ENERGY STORED IN ANINDUCTOR?

E = 0.5CU2

E = 0.5LI2

E = 1/2 BLv

E = BLv

Question 9

On an AC Mains supply of 230volts, what is the minimum voltage value whichcapacitors must be rated at?

250 VOLTS400 VOLTS600 VOLTS220 VOLTS



Question 10

TO CALCULATE CAPACITANCE, WHICH OF THE FOLLOWING FORMULAS IS TRUE

V = Q/C

V = C/Q

Q = V/C

Q = C/V

Question 11

IF A CURRENT OF 12.5A FLOWS FOR A TIME OF 2 MINUTES CALCULATE THE AMOUNTOF CHARGE TRANSFERRED

150 VOLTS

1500 FARADS

1500 COULOMBS

9.6 COULOMBS

Question 12

IF A CHARGE OF 500 MICRO COULOMBS IS STORED IN A 25 MICRO FARAD CAPACITOR,

WHAT WILL THE P.D. ACROSS THE PLATES BE?

0.2 volts

20 volts

12500 milli volts

1250 milli volts

Question 13

CALCULATE THE CHARGE IF A 200 MICRO FARAD CAPACITOR IS CONECTED TO A 200

VOLTS SUPPLY

0.04 COULOMBS

0.4 COULOMBS

0.04 JOULES

0.4 JOULES

Question 14

CALCULATE THE EQUIVALENT CAPACITANCE OF 3 CAPACITORS WHEN CONNECTEDIN SERIES.

THERE VALUES ARE :

5 MICRO FARAD, 10 MICRO FARAD AND 30 MICRO FARAD

2 MICRO FARAD

0.02 MICRO FARAD

0.33 MICRO FARAD

3 MICRO FARAD

Question 15

THE ELECTRIC FIELD STRENGTH OF A CAPACITOR IS DETERMINED BY THE VOLTAGE

BETWEEN THE PLATES DIVIDED BY THE THICKNESS OF THE DIALECTRIC.

BUT WHAT UNITS ARE ELECTRIC FIELD STRENGTH MEASURED IN ?

COULOMBS PER SQUARE METRE

AMPS PER SECOND

VOLTS PER METRE

WATTS PER SECOND

Question 16

WHICH IS CORRECT FORMULA FOR CALCULATING THE ENERGY STORED IN ACAPACITOR

E = 0.5CU2

E = 0.5LI2

C = W/0.5U U = W/0.5C



Question 17

AS A GENERAL RULE, WHEN A CAPACITOR IS FULLY CHARGED WHAT WILL IT BLOCK?

A D.C. VOLTAGE

AN A.C. VOLTAGE

A D.C. CURRENT

AN A.C. CURRENTQuestion 18

THE CAPACITOR FITTED IN THE STARTER SWITCH OF A FLUORESCENT LIGHT FITTING

IS FOR WHAT REASON ?

TO MAKE IT START QUICKER

TO STOP IT FLICKERING WHEN IT'S STARTING

TO IMPROVE THE POWER FACTOR

TO SUPPRESS RADIO FREQUENCY INTERFERENCE

Question 19

FIXED CAPACITORS CAN BE PLACED INTO THREE GENERAL CLASSES RELATED TO

THEIR DIALECTRICS

WHICH CLASS WOULD AN ELECTROLYTIC CAPACITOR BE IN ? LOW LOSS CAPACITOR

MEDIUM LOSS CAPACITOR

POLARISED CAPACITOR

HIGH STABILITY CAPACITOR

Question 20

If the Peak Voltage is 1 Volt AC what is the RMS value

0.637 V

1.414V

0.707V1.618V



ANSWERS!!!!!!!!!!!!!!!

Question 1

WHAT UNIT WILL THE TOTAL ENERGY STORED IN A CAPACITOR BE MEASURED IN ?

Correct Answer: JOULES

Question 2

FOR MAXIMUM CAPACITANCE THE PLATES OF A CAPACITOR MUST BE

Correct Answer: AS CLOSE AS POSSIBLE

Question 3

INDUCTANCE IS MEASURED IN WHAT UNITS ?

Correct Answer: HENRIES

Question 4

IF A POLARISED (ELECTROLYTIC) CAPACITOR WAS CONNECTED THE WRONG WAY

ROUND TO A SUPPLY, WHAT WOULD HAPPEN ?Correct Answer: IT WOULD BE DESTROYED

REMEMBERPOLARISED CAPS SHOULD NOT BE CONNECTED TO AN ALTERNATING VOLTAGE AND

MUST BE CORRCTLY CONNECTED TO A DC SUPPLY.

Question 5

CALCULATE THE ENERGY STORED IN A 200 MICRO FARAD CAPACITOR CONNECTED TO

A 200 VOLT SUPPLYCorrect Answer: 4 JOULES

REMEMBER

E = 0.5CU2

Question 6

IF 3 10 MICRO FARAD CAPACITORS ARE CONNECTED IN SERIES, THE CHARGE ON EACH

CAPACITOR WILL BECorrect Answer: THE SAME

Question 7

WHY ARE DISCHARGE RESISTORS OFTEN CONNECTED TO LARGE CAPACITORSCorrect Answer: TO SAFELY DISSIPATE THE CHARGE HELD THUS REDUCING SHOCK

RISK

Question 8

WHAT IS THE FORMULA NEEDED TO CALCULATE THE ENERGY STORED IN AN

INDUCTOR?

Correct Answer:

E = 0.5LI2

Question 9

On an AC Mains supply of 230volts, what is the minimum voltage value which capacitors must be ratedat?Correct Answer: 400 VOLTS



Question 10

TO CALCULATE CAPACITANCE, WHICH OF THE FOLLOWING FORMULAS IS TRUE

Correct Answer: V = Q/C

Question 11

IF A CURRENT OF 12.5A FLOWS FOR A TIME OF 2 MINUTES CALCULATE THE AMOUNT

OF CHARGE TRANSFERRED

Correct Answer: 1500 COULOMBS

REMEMBER THE CHARGE IS Q

AND

Q = I x t

Question 12

IF A CHARGE OF 500 MICRO COULOMBS IS STORED IN A 25 MICRO FARAD CAPACITOR,

WHAT WILL THE P.D. ACROSS THE PLATES BE?

Correct Answer: 20 volts

Question 13

CALCULATE THE CHARGE IF A 200 MICRO FARAD CAPACITOR IS CONECTED TO A 200VOLTS SUPPLY

Correct Answer: 0.04 COULOMBS

Question 14

CALCULATE THE EQUIVALENT CAPACITANCE OF 3 CAPACITORS WHEN CONNECTED

IN SERIES.

THERE VALUES ARE :

5 MICRO FARAD, 10 MICRO FARAD AND 30 MICRO FARAD

Correct Answer: 3 MICRO FARAD

Question 15

THE ELECTRIC FIELD STRENGTH OF A CAPACITOR IS DETERMINED BY THE VOLTAGE

BETWEEN THE PLATES DIVIDED BY THE THICKNESS OF THE DIALECTRIC.

BUT WHAT UNITS ARE ELECTRIC FIELD STRENGTH MEASURED IN ?

Correct Answer: VOLTS PER METREREMEMBER

E = U/d

Question 16

WHICH IS CORRECT FORMULA FOR CALCULATING THE ENERGY STORED IN A

CAPACITORCorrect Answer:

E = 0.5CU2

Question 17

AS A GENERAL RULE, WHEN A CAPACITOR IS FULLY CHARGED WHAT WILL IT BLOCK?

Correct Answer: A D.C. CURRENT

Question 18

THE CAPACITOR FITTED IN THE STARTER SWITCH OF A FLUORESCENT LIGHT FITTING

IS FOR WHAT REASON ?

Correct Answer: TO SUPPRESS RADIO FREQUENCY INTERFERENCE



Question 19

FIXED CAPACITORS CAN BE PLACED INTO THREE GENERAL CLASSES RELATED TO

THEIR DIALECTRICSWHICH CLASS WOULD AN ELECTROLYTIC CAPACITOR BE IN ?

Correct Answer: POLARISED CAPACITOR

Question 20

If the Peak Voltage is 1 Volt AC what is the RMS value

Correct Answer: 0.707V

Electrical quizes with answers review

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