Tag: effects of electric current

Questions Related to effects of electric current

AC is not suitable for electrolysis because

ac and dc ac vs dc electro-magnetism effects of electric current physics

  1. It has large current

  2. It has high voltage

  3. Polarity of the current changes

  4. Polarity of the current remains the same

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Correct Option: A
Explanation:

In electrolysis the ionization of the electrolyte takes place where the positive and negative charges move towards opposite electrodes. For this the electrodes are required to be maintained at opposite polarity as long as the process continuous which is possible while supplying a dc current. But if we pass an ac current the polarity of the electrodes will be continuously changing and the ions will not be attracted towards any particular electrode resulting in no ionization. Hence electrolysis cannot take place with ac current.

Which of the statements is false?
AC: Alternating current
DC: Direct Current 

ac and dc ac vs dc electro-magnetism effects of electric current physics

  1. AC generation is done by a generator

  2. DC generation is done by electrochemical cells

  3. AC generation can be done by electrochemical cells

  4. None

Show answer
Correct Option: C
Explanation:

Electrochemical cells produce DC.

AC is generated by a generator.

What is not a characteristic of alternating current?

ac and dc ac vs dc electro-magnetism effects of electric current physics

  1. Periodic in nature

  2. Time period does not change

  3. Maximum positive amplitude is more than maximum negative amplitude

  4. Average value is 0

Show answer
Correct Option: C
Explanation:
Characteristics of alternating current :

1. Periodic in nature
2. Time period does not change
3. Average value is zero.

Why is AC preferred over DC for transmission of electrical power

ac and dc ac vs dc electro-magnetism effects of electric current physics

  1. AC to DC conversion and vice versa is very easy

  2. Transmission losses in AC are lower

  3. AC transmission is unaffected by random phase change

  4. Frequency of AC do not change

Show answer
Correct Option: B
Explanation:

Transmission losses are given as $I^2R$. In AC, voltage transformation to higher(and also lower) values is easier at constant power. So, voltage is increased before transmission reducing current and hence reducing transmission losses.

In the experiment of half deflection method the resistance R should be

physics effects of electric current meter bridge meter bridge and problems on it galvanometer

  1. > S

  2. $\approx$ S

  3. < S

  4. $\approx$ G

Show answer
Correct Option: A
Explanation:

In half deflection method, Rg = (R)*(S)/(R-S) .
Here , Rg= Galvanometer resistance, R = high resistance in series with the galvanometer, S = low resistance in parallel with the galvanometer. We want to approximate Rg in terms of S which we are able to vary in the experiment . If R>>S then Rg = S.                                      

Wires used in homes are usually covered with materials like plastic or rubber. This is done to

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. Prevent rusting

  2. Make handling easier

  3. Prevent shocks & short circuits

  4. Make them look beautiful

Show answer
Correct Option: C
Explanation:

Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves.

therefore it prevent us from shocks and short circuits.

Find odd man out.
Dry cell, Solar cell, Generator, Electric bulbs.

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. Generator

  2. Solar Cell

  3. Dry Cell

  4. Electric bulbs

Show answer
Correct Option: D
Explanation:

It is an electrical appliance, rest are sources of electricity.

State whether given statement is True or False
Earth connection saves the user from electric shocks.

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. True

  2. False

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Correct Option: A
Explanation:

The current takes the path that is having less resistance . Hence lesser the resistance higher the current and higher the resistance lower the current. So in case of shock current passes though you. A normal person have a resistance of about $10\times 10^3\Omega $ and as there is no different path for the current to move hence its passes to ground though you.  

but in case a earth connection the current have almost no resistance path through the ground wire to the ground.
Therefore it helps in saving the user from electric shocks. 

All wires used in electric circuits should be covered with

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. a coloured material

  2. an insulating material

  3. a conducting material

  4. none of these

Show answer
Correct Option: B
Explanation:

he most important reason why electrical wires are covered in insulating material is to protect people from electrical shock, and  protection from short circuit.

State whether given statement is True or False
All electrical appliances should be properly earthed.

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. True

  2. False

Show answer
Correct Option: A
Explanation:

All electrical appliances should be properly earthed because to prevent us from shock. This statement is true.