# Multiple choice question for engineering

## Set 1

1. Reciprocal of reluctance is __________

a) Permeance

b) Susceptibility

c) Resistance

d) Conductance

### View Answer

2. Reactance is ________________ to the length of the material.

a) Directly proportional

b) Inversely proportional

c) Not related

d) Depends on the area of the material

### View Answer

3. Reactance is ________________ to the area of cross section the material.

a) Directly proportional

b) Inversely proportional

c) Not related

d) Depends on the length of the material

### View Answer

4. When the length of the material increases, what happens to reluctance?

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

### View Answer

5. When the area of cross section of the material increases, what happens to reluctance?

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

### View Answer

6. Unit of reluctance is?

a) AWb

b) A^{2}/Wb

c) Wb/A

d) A/Wb

### View Answer

7. The electrical equivalent of reluctance is?

a) Resistance

b) Inductance

c) Capacitance

d) Conductance

### View Answer

8. As the magnetic field strength increases, reluctance?

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

### View Answer

9. As the magnetic flux density increases, the reluctance _____________

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

### View Answer

10. Calculate the reluctance when the magnetomotive force is 10A turns and the flux is 5Wb.

a) 0.5A/Wb

b) 5A/Wb

c) 10A/Wb

d) 2A/Wb

### View Answer

## Set 2

1. For addition and subtraction of phasors, we use the _________ form.

a) Rectangular

b) Polar

c) Either rectangular or polar

d) Neither rectangular nor polar

### View Answer

2. For multiplication and division of phasors, we use ____________ form.

a) Rectangular

b) Polar

c) Either rectangular or polar

d) Neither rectangular nor polar

### View Answer

3. If a voltage of 2+5j and another voltage of 3+ 6j flows through two different resistors, connected in series, in a circuit, find the total voltage in the circuit.

a) 2+5j V

b) 3+6j V

c) 5+11j V

d) 5+10j V

### View Answer

4. Find the total current in the circuit if two currents of 4+5j flow in the circuit.

a) 4+5j A

b) 4A

c) 5A

d) 8+10j A

### View Answer

5. What is the correct expression of ω?

a) ω=2*pi

b) ω=2*pi*f

c) ω=pi*f

d) ω=2f^{2}

### View Answer

6. Find the value of ω if the frequency is 5Hz?

a) 3.14 rad/s

b) 31.4 rad/s

c) 34 rad/s

d) 341 rad/s

### View Answer

7. When one sine wave passes through the zero following the other, it is _________

a) Leading

b) Lagging

c) Neither leading nor lagging

d) Either leading or lagging

### View Answer

8. A phasor has frozen at 30 degrees, find the value of the phase angle.

a) 30 degrees

b) 60 degrees

c) 120 degrees

d) 180 degrees

### View Answer

9. The time axis of an AC phasor represents?

a) Time

b) Phase angle

c) Voltage

d) Current

### View Answer

10. The length of the phasor represents?

a) Magnitude of the quantity

b) Direction of the quantity

c) Neither magnitude nor direction

d) Either magnitude or direction

### View Answer

## Set 3

1. In an RC series circuit ________

a) Applied voltage lags capacitor voltage

b) Applied voltage leads capacitor voltage

c) Current and voltage are in phase

d) Applied voltage and capacitive voltage are in phase

### View Answer

2. Which, among the following is the correct expression for φ?

a) φ=tan^{-1}(Xc/R)

b) φ=tan^{-1} (R/Xc)

c) φ=tan^{-1} (Xc*R)

d) φ=cos^{-1} (Xc/R)

### View Answer

^{-1}(Xc/R).

3. For an RC circuit, the phase angle is always ________

a) Positive

b) Negative

c) 0

d) 90

### View Answer

4. What is φ in terms of voltage?

a) φ=cos^{-1}V/VR

b) φ=cos^{-1}V*VR

c) φ=cos^{-1}VR/V

d) φ=tan^{-1}V/VR

### View Answer

^{-1}VR/V.

5. An RC network is one which consists of?

a) Resistor and capacitor in parallel

b) Resistor and capacitor in series

c) Resistor and inductor in parallel

d) Resistor and inductor in series

### View Answer

6. At DC, capacitor acts as?

a) Open circuit

b) Short circuit

c) Resistor

d) Inductor

### View Answer

7. In an RC series circuit, when the switch is closed and the circuit is complete, what is the response?

a) Response does not vary with time

b) Decays with time

c) Increases with time

d) First increases, then decreases

### View Answer

8. The expression for current in an RC circuit is?

a) i=(V/R)e^{(t/RC)}

b) i=(V/R)e^{(-t/RC)}

c) i=(V/R)/e^{(t/RC)}

d) i=(V/R)/e^{(-t/RC)}

### View Answer

^{(-t/RC)}.

9. An 8microF capacitor is connected in series with a 0.5 megaohm resistor. The DC voltage supply is 200V. Calculate the initial charging current.

a) 100 microA

b) 500 microA

c) 400 microA

d) 1000microA

### View Answer

^{6})= 400*10

^{-6}A= 400 microA.

10. While discharging, what happens to the current in the capacitive circuit?

a) Decreases linearly

b) Increases linearly

c) Decreases exponentially

d) Increases exponentially

### View Answer

## Set 4

1. A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the current in the circuit.

a) 2.2A

b) 4.2A

c) 6.2A

d) 8.2A

### View Answer

^{2}+XL

^{2})=12.2ohm. V=IZ, therefore 100/12.2= 8.2A.

2. A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the phase difference.

a) -55.1

b) 55.1

c) 66.1

d) -66.1

### View Answer

^{-1}(XL/R)=55.1 Since this is an inductive circuit, the current will lag, hence φ= -55.1.

3. A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the voltage across the resistor.

a) 31.8V

b) 57.4V

c) 67.3V

d) 78.2V

### View Answer

^{2}+XL

^{2})=12.2ohm. V=IZ, therefore 100/12.2= 8.2A. Voltage across resistor= 8.2*7=57.4V.

4. A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the voltage across the inductor.

a) 57.4V

b) 42.6V

c) 65.2V

d) 76.2V

### View Answer

^{2}+XL

^{2})=12.2ohm. V=IZ, therefore 100/12.2= 8.2A. Voltage across resistor= 8.2*7=57.4V. Voltage across inductor =100-VR= 42.6V.

5. A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a x V 50Hz sinusoidal supply. The current in the circuit is 8.2A. Calculate the value of x.

a) 10V

b) 50V

c) 100V

d) 120V

### View Answer

^{2}+XL

^{2})=12.2ohm. V=IZ, Therefore V=12.2*8.2=100V.

6. Which, among the following, is the correct expression for φ.

a) φ=tan^{-1} (XL/R)

b) φ=tan^{-1} (R/XL)

c) φ=tan^{-1} (XL*R)

d) φ=cos^{-1} (XL/R)

### View Answer

^{-1}(XL/R).

7. For an RL circuit, the phase angle is always ________

a) Positive

b) Negative

c) 0

d) 90

### View Answer

8. What is φ in terms of voltage?

a) φ=cos^{-1}V/VR

b) φ=cos^{-1}V*VR

c) φ=cos^{-1}VR/V

d) φ=tan^{-1}V/VR

### View Answer

^{-1}VR/V.

9. An RL network is one which consists of?

a) Resistor and capacitor in parallel

b) Resistor and capacitor in series

c) Resistor and inductor in parallel

d) Resistor and inductor in series

### View Answer

10. At DC, inductor acts as ___________

a) Open circuit

b) Short circuit

c) Resistor

d) Inductor

### View Answer

## Set 5

1. Materials which allow the passage of electric current are known as______

a) Insulators

b) Conductors

c) Dielectrics

d) Semi-conductors

### View Answer

2. A wire of length 2m and another wire of length 5m are made up of the same material and have the same area of cross section, which wire has higher resistance?

a) Both have equal resistance

b) The 2m wire has higher resistance

c) The 5m wire has higher resistance

d) The value of resistance cannot be determined from the given data

### View Answer

3. A wire having an area of cross section = 10sqm and another wire having an area of cross section= 15sqm, have the same length and are made up of the same material. Which wire has more resistance?

a) Both have equal resistance

b) The 10sqm wire has higher resistance

c) The 15sqm wire has higher resistance

d) The value of resistance cannot be determined from the given data

### View Answer

4. Which of the following statements are true with regard to resistance?

a) Resistance is directly proportional to length of the wire

b) Resistance is directly proportional to area of cross section of the wire

c) Resistance is inversely proportional to the length of the wire

d) All the statements are false

### View Answer

5. A wire has the same resistance as the one given in the figure. Calculate its resistivity if the length of the wire is 10m and its area of cross section is 2m.

a) 16 ohm-metre

b) 8 ohm-metre

c) 16 kiloohm-metre

d) 8 kiloohm-metre

### View Answer

6. Which, among the following is a unit for resistivity?

a) ohm/metre

b) ohm/metre^{2}

c) ohm-metre

d) ohm-metre^{2}

### View Answer

^{2}/metre. Hence the unit of resistivity is ohm- metre.

7. What is the resistivity of Copper?

a) 1.59*10^{-8}ohm^{-m}

b) 2.7*10^{-8}ohm^{-m}

c) 7.3*10^{-8}ohm^{-m}

d) 5.35*10^{-8}ohm^{-m}

### View Answer

^{-8}ohm

^{-metre}.

8. Calculate the ratio of the resistivity of 2 wires having the same length and same resistance with area of cross section 2m^{2} and 5m^{2} respectively.

a) 5:7

b) 2:7

c) 2:5

d) 7:5

### View Answer

9. Which of the following statements are true with regard to resistivity?

a) Resistance depends on the temperature

b) Resistance does not depend on the temperature

c) Resistance does not depend on length

d) All the statements are false

### View Answer

10. The reciprocal of resistivity is________

a) Conductance

b) Resistance

c) Conductivity

d) Impedance