Tag: devices used to protect from shock of electric current

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

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

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

  1. silver

  2. aluminium

  3. copper

  4. both b and c

Show answer
Correct Option: D
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

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

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

  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

Show answer
Correct Option: A
Explanation:

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

Find odd one out.
Water heater, Electric iron, Electric toaster, Tube light.

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

  1. Tube light

  2. Water heater

  3. Electric iron

  4. Electric toaser

Show answer
Correct Option: A
Explanation:

Tube light converts electric energy into light energy. Rest all produce heat.

Alternating current produced in india has a frequency of _______.

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

  1. 220 Hz

  2. 120 Hz

  3. 15 Hz

  4. 50 Hz

Show answer
Correct Option: D
Explanation:

Alternating current produced in india has a frequency of 50 Hz. i.e. the coil is rotated at the role of 50 revolution per second.

High tension wires has

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

  1. high resistance.

  2. low resistance.

  3. high young's modulus.

  4. low young's modulus.

Show answer
Correct Option: B
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.

In domestic electrical circuit, switches are used in

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

  1. Neutral wire

  2. Earth wire

  3. Live wire

  4. All of these

Show answer
Correct Option: C
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.

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

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

  1. Low

  2. High

  3. Equal

  4. None

Show answer
Correct Option: A
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.

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 

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

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

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

  3. $10 \times (10) ^ {21}$

  4. $2 \times (10) ^ {20}$

Show answer
Correct Option: D
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 , $n=\dfrac E{E'}$
$=\dfrac{640}{32\times 10^{-19}}$
$=2\times 10^{20}$