Tag: domestic and commercial circuit

Questions Related to domestic and commercial circuit

According to new convention,_____colour is used for live wire. Fill in the blank. 

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. Red

  2. Brown

  3. Light blue

  4. Green

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Correct Option: B
Explanation:

According to new convention, brown colour is coded for live wire, light blue is coded for neutral wire and green or yellow is coded for earth wire.

Which colour is used for earth wire?

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. Green

  2. Yellow

  3. Both of these

  4. None of these

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Correct Option: C
Explanation:

Either green or yellow is used for earth wires.

Name the colour used in insulated wired of electrical appliance.

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. Blue

  2. Green

  3. Brown

  4. All of these

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Correct Option: D
Explanation:

Blue, green and brown are used as insulated wired.

Each electrical appliance is provided with a _______ core flexible cable. Fill in the blank.

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. 3

  2. 2

  3. 1

  4. 4

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Correct Option: A
Explanation:

Each electrical appliance is provided with three (3) core flexible cables. The insulation on the three wires is of different colours i.e  Brown for live wire, blue for neutral wire and green or yellow for earth wire.

Every electric appliance is marked with

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. power

  2. potential difference

  3. charge

  4. resistance

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Correct Option: A,B
Explanation:

Every electric appliance is marked with it's power and potential difference at which it works. This marking is called rating of an electrical appliances.

State SI unit of electric power.

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. Watt

  2. Kilo watt

  3. Joule

  4. Kilowatt hour

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Correct Option: A
Explanation:

SI unit of electric power is Watt
1 Watt = 1  Volt $\times$ 1 ampere.

In a city, electricity costs $0.12 per kilowatt-hour. A bulb of 150-watt operates for 5 hours. Calculate the cost of electricity which is consumed by the bulb.

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. $0.009

  2. $0.09

  3. $0.90

  4. $9.00

  5. $90.00

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Correct Option: B
Explanation:

Cost $=(0.150 kWh) (hr)  \left ( 12 \dfrac {cent}{kWh} \right )= 9 cent
=$0.09$

For a domestic $AC$ supply of $220\ V$ at $50$ cycles per second the potential difference between the terminals of a two-pin electric outlet in a room is given by

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. $V(t) = 220\sqrt {2}\cos (100\pi t)$

  2. $V(t) = 220\cos (50t)$

  3. $V(t) = 220\cos (100\pi t)$

  4. $V(t) = 220\sqrt {2}\cos (50 t)$

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Correct Option: A
Explanation:

Rms value of voltage  $V _{rms} =220 $ volts

Peak value of voltage  $V _o = \sqrt{2}V _{rms}$
$\therefore$ $V _{o} = 220\sqrt{2}$volts   
Frequency  $\nu =50$ $Hz$
$\implies$  $w = 2\pi \nu = 2\pi (50)  = 100\pi$
Thus potential difference is given by  $V = V _o \cos wt$
$\therefore$  $V= 220\sqrt{2} \cos (100 \pi t)$

Which instrument is not used to convert electric energy into heat energy?

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. Room heater

  2. Electric Iron

  3. Electric Bell

  4. Electric water heater

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Correct Option: C
Explanation:

Electric Bell is not used to convert electric energy into heat energy as there is no  use of heat in functioning of an electric bell.In electric bell electrical energy is used to convert sound energy.First it converts electric energy into mechanical energy and which is used to produce sound energy.

Therefore,C is correct option.

Household electrical appliances are joined using ________ combination of resistors

physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

  1. Parallel

  2. Alternating

  3. Continuous

  4. Series

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Correct Option: A
Explanation:

In a house, there are many electrical appliances that have to run independent of each other. If one appliance is turned on or off it should not affect the other appliances. Thus even if a single appliance is taken out of the circuit (turned off / open switched ) the circuit breaks and hence the current cannot flow in the circuit so every thing turns off.

 So even if a single appliance is taken out of the circuit (turned off / open switched ) the circuit breaks and hence the current cannot flow in the circuit .
In parallel, even if an appliance gets damaged or is turned off ,the current always has other independent dedicated parallel paths to other appliances and hence every appliance is still works well.