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

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

  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. $V(t) = 220\sqrt {2}\cos (50 t)$
Reveal answer Fill a bubble to check yourself
A Correct answer
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  $V = V _o \cos wt$
$\therefore$  $V= 220\sqrt{2} \cos (100 \pi t)$

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

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

  1. Room heater

  2. Electric Iron

  3. Electric Bell

  4. Electric water heater
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

Household electrical appliances are joined using ________ combination of resistors

  1. Parallel

  2. Alternating

  3. Continuous

  4. Series
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

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

Which statement is wrong from the following?

  1. The earthing wire is green coloured.

  2. In India, current flowing through wire is AC and its frequency is $50 \,Hz$.

  3. In India, voltage between two wires is $110 \,V$.

  4. T.V., Tublight, bulbs are connected with $5\, A$ line.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In India, current flowing through wire is A.C and its frequency is $50Hz$ and voltage $220V$.But, Option C said voltage between two wires is 110V110V, which is wrong.

Therefore, C is correct option.

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

Which of the following statements is true?

  1. In tree type distribution of electric power, fuses are present only on the main board.

  2. In ring type distribution of electric power, there is an individual fuse for each appliance.

  3. Ring type distribution of electric power is advantageous than the tree type distribution.

  4. All the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In tree type distribution of electric power, fuses are present only on the distribution board where as in ring type, there is an individual fuse for each appliance. As there is an individual fuse for each appliance in ring type, only faulty appliance will not work and all the other appliances will not be affected. It is easier to install. So, ring type is advantageous than that of tree type. Hence, choice is (4)