Tag: devices used to protect from shock of electric current

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Questions Related to devices used to protect from shock of electric current

Multiple choice physics household circuits precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

Wires used for electric supply go are generally made up of:

  1. silver

  2. aluminium

  3. copper

  4. both b and c
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electric is generated at power station. It is brought to one house by two thick copper wires or aluminium wires fixed once fall electric poles

Multiple choice physics electric circuits precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

Which of the following is not a safety measure commonly used in electric circuits.

  1. An electric fuse is connected in parallel

  2. Proper earthing of all electric circuit is done

  3. Fuse protects the circuit from overloading

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

An electric fuse is connected in parallel. This is not a safety measure. Fuse is always connected in series.

Multiple choice physics household circuits precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

High tension wires has

  1. high resistance.

  2. low resistance.

  3. high young's modulus.

  4. low young's modulus.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

High tension wire is made by twisting together a number of thin wires insulated from each other so as to provide large surface area. It helps to radiate more heat and prevents burning of wire.

Multiple choice physics electric circuits precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

In domestic electrical circuit, switches are used in

  1. Neutral wire

  2. Earth wire

  3. Live wire

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Switches are connected in live wire so that when the switch is in off position, no current flows through circuit. As a result there will not be any danger of electrical shock.

Multiple choice physics household circuits precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

A high tension wire has a _____ resistance. Fill in the blank.

  1. Low

  2. High

  3. Equal

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A high tension wire has a low resistance and large surface area. Instead of taking a single thick wire of low resistance, it is made by twisted together a number of thin wires insulated from each other so as tat it can radiate the head provided.

Multiple choice physics household circuits precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

A bulb of 40W is producing a light of wavelength 620 nm with 80% of eficiency then no of photons emitted by the bulb in 20 sec are 

  1. $2 \times (10) ^ {18}$

  2. <span>$10 \times (10) ^ {18}$</span>

  3. <span>$10 \times (10) ^ {21}$</span>

  4. <span>$2 \times (10) ^ {20}$</span>
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Energy of photon emitted by a bulb,

$E=\dfrac{80}{100}\times 40\times 20=640$
Wavelength of light, $\lambda=620nm$
Energy of photons $E'=\dfrac{hc}{\lambda}$
$=3.2\times 10^{-19}J$
$\therefore$ No of photons emitted , $n=\dfrac E{E'}$
$=\dfrac{640}{32\times 10^{-19}}$
$=2\times 10^{20}$