Owen Ryan Ang
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A compilation of objective type questions in Electrical Engineering

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CURRENT ELECTRICITY

Frage 1 von 35

1

What are the minimum requirements to cause the flow of current?

Wähle eine der folgenden:

  • A voltage source, an ammeter, a conductor and an insulator

  • A voltage source, a switch and a resistor

  • A voltage source and a conductor

  • A voltage source, a conductor and an insulator

Erklärung

Frage 2 von 35

1

Out of the following, select the best conductor of electricity.

Wähle eine der folgenden:

  • Graphite

  • China Clay

  • Porcelain

  • None of these

Erklärung

Frage 3 von 35

1

Which of the following statements is correct?

Wähle eine der folgenden:

  • The resistance does not play an important role in electrical engineering.

  • The resistance of a wire does not depend upon its material.

  • The resistance of most of the materials is independent of the temperature.

  • The resistance of conductor is the hindrance by which the conductor opposes the flow of the current.

Erklärung

Frage 4 von 35

1

Resistance of a conductor increases when

Wähle eine der folgenden:

  • its length increases

  • its area increases

  • both length and area increases

  • specific resistance is kept constant

Erklärung

Frage 5 von 35

1

The specific resistance ρ depends upon

Wähle eine der folgenden:

  • The area of cross-section and the length of the conductor

  • The material of the conductor, its area of cress-section and length

  • The nature of the material of the conductor only

  • The area of cross-section of the conductor

Erklärung

Frage 6 von 35

1

The specific resistance ρ is defined as

Wähle eine der folgenden:

  • resistance of a conductor which has a length of 1 m and cross-section of 1 m2 at 20C

  • resistance of any conductor at 25C

  • resistance of any conductor at 20C

  • resistance of a conductor which has a length of 1 m and cross-section of 1 cm2 at 20C

Erklärung

Frage 7 von 35

1

The resistance of a conductor, when its temperature is increased

Wähle eine der folgenden:

  • remains constant

  • increases

  • varies

  • decreases

Erklärung

Frage 8 von 35

1

It was experimentally found by James Prescott Joule that the heat produced in a current carrying conductor is proportional to

Wähle eine der folgenden:

  • the square of the current

  • square of resistance

  • the current

  • inversely proportional to time

Erklärung

Frage 9 von 35

1

The value of Joule's mechanical equivalent of heat, J, is equal to

Wähle eine der folgenden:

  • 4.2 calories per Joule

  • 2.4 Joules per calorie

  • 4.2 Joules per calorie

  • 4.2 Joules

Erklärung

Frage 10 von 35

1

Temperature coefficient of a conductor is defined as the

Wähle eine der folgenden:

  • increase in resistance per ohm per degree centigrade

  • increase in resistance per degree centigrade

  • increase in resistance per degree absolute

  • decrease in resistance per ohm per degree centigrade

Erklärung

Frage 11 von 35

1

When current flows in a conductor, heat is produced because

Wähle eine der folgenden:

  • heat α I²

  • of electronic collision

  • of interatomic collision

  • of Joule's law

Erklärung

Frage 12 von 35

1

Heating effect of current has undesirable side effect in

Wähle eine der folgenden:

  • electric oven

  • electric iron

  • immersion heater

  • vacuum cleaner

Erklärung

Frage 13 von 35

1

The resistance of carbon (filament in carbon-filament lamps) when its temperature is decreased

Wähle eine der folgenden:

  • increases

  • decreases

  • remains the same

  • increases enormously

Erklärung

Frage 14 von 35

1

The curve representing Ohm's law is

Wähle eine der folgenden:

  • a parabola

  • linear

  • sine function

  • a hyperbola

Erklärung

Frage 15 von 35

1

The condition in Ohm's law is that

Wähle eine der folgenden:

  • ratio V/I should be constant

  • current should be proportional to voltage

  • the temperature should remain constant

  • the temperature should vary

Erklärung

Frage 16 von 35

1

Ohm's law does not apply to

Wähle eine der folgenden:

  • conductors

  • conductors when there is change in temperature

  • semiconductor

  • a.c. circuit

Erklärung

Frage 17 von 35

1

Ohm's law is applicable to

Wähle eine der folgenden:

  • electric arc

  • rectifying devices

  • gas discharge lamps

  • none of these

Erklärung

Frage 18 von 35

1

Ohm's law can be applied with certain reservations to

Wähle eine der folgenden:

  • rectifying devices

  • semiconductors

  • electrolytes

  • thermionic valves

Erklärung

Frage 19 von 35

1

The presence of an electric current is made known by

Wähle eine der folgenden:

  • flashing

  • effects produced

  • cracking

  • electric shock

Erklärung

Frage 20 von 35

1

An electric current can neither be ____ nor ____.

Wähle eine der folgenden:

  • felt, seen

  • seen, touched

  • seen, produced by any effect

  • produced, felt

Erklärung

Frage 21 von 35

1

The presence of the current is only made known by the effect it produces. Three important effects are

Wähle eine der folgenden:

  • heating, electric shock and generation

  • generation, chemical and electric shock

  • heating, magnetic and electric shock

  • heating, magnetic and chemical

Erklärung

Frage 22 von 35

1

Voltage applied across a circuit, acts as

Wähle eine der folgenden:

  • mass of electrons

  • negative ions

  • a component of current

  • a force

Erklärung

Frage 23 von 35

1

In a series circuit the current is

Wähle eine der folgenden:

  • constant

  • always zero

  • proportional to the resistance

  • different from resistors

Erklärung

Frage 24 von 35

1

In a parallel circuit the potential difference across the resistance

Wähle eine der folgenden:

  • varies

  • is different from the applied voltage

  • is sometimes constant

  • is always constant

Erklärung

Frage 25 von 35

1

The resistance R1 and R2 are connected in parallel. The ratio of values of resistance R1 : R2 is 4 : 1. The currents in R1 : R2 will be equal to

Wähle eine der folgenden:

  • 1 : 4

  • 1 : 1

  • 4 : 1

  • 4 : 4

Erklärung

Frage 26 von 35

1

A resistance of 4 ohms is connected across 100 V supply. When another resistor 'R' ohms is connected in parallel with 4 ohms, the total current taken from supply was found to be 50 A. The value of resistance 'R' is

Wähle eine der folgenden:

  • 2 ohms

  • 3 ohms

  • 5 ohms

  • 4 ohms

Erklärung

Frage 27 von 35

1

The voltage applied across an electric press was reduced by 50%. The power consumed by the press will be reduced by

Wähle eine der folgenden:

  • 25%

  • 75%

  • 60%

  • 50%

Erklärung

Frage 28 von 35

1

Two electric presses are connected in parallel. The resistance of the first press is 100 ohms and that of the second is 300 ohms. The total current taken by both the presses is 4 A. The ratio of current taken by first : second will be equal to

Wähle eine der folgenden:

  • 2 : 3

  • 1 : 3

  • 3 : 1

  • 1.2 : 3

Erklärung

Frage 29 von 35

1

Three elements having conductance G1. G2 and G3 are connected in parallel. Their combined conductance will be

Wähle eine der folgenden:

  • G1 + G2 + G3

  • 1/(G1 + G2 + G3)

  • (G1G2 + G2G3 + G3G1)/(G1 + G2 + G3)

  • 1/(1/G1 + 1/G2 + 1/G3)

Erklärung

Frage 30 von 35

1

Four resistance R1, R2, R3 and R4 are connected in series against 220 V supply. The resistances are such that R1 > R2 > R3 > R4. The least power consumption will be in

Wähle eine der folgenden:

  • resistor R1

  • resistor R4

  • resistor R3

  • resistor R2

Erklärung

Frage 31 von 35

1

When current flows through heater coil it glows but supply wiring does not glow because

Wähle eine der folgenden:

  • supply wiring is covered with insulation layer

  • current through supply line flows at slower speed

  • supply wires are made of superior material

  • resistance of heater coil is more than that of supply wires

Erklärung

Frage 32 von 35

1

Resistors commonly used in power circuits are

Wähle eine der folgenden:

  • carbon resistors

  • etched circuit resistors

  • wire wound resistors

  • deposited metal resistors

Erklärung

Frage 33 von 35

1

International ohm is defined in terms of resistance of

Wähle eine der folgenden:

  • a column of mercury

  • a cube of carbon

  • unit length of metal wire

  • a cube of copper

Erklärung

Frage 34 von 35

1

Which of the following has negative coefficient of resistance?

Wähle eine der folgenden:

  • wire wound resistor

  • non-metals

  • thermistor

  • metals

Erklärung

Frage 35 von 35

1

The current carrying capability of the fuse material depends on

Wähle eine der folgenden:

  • length

  • material

  • cross-sectional area

  • all of these

Erklärung