Tag: effects of electric current

Quizzes (19) Questions (134)

Questions Related to effects of electric current

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

AC is not suitable for electrolysis because

  1. It has large current

  2. It has high voltage

  3. Polarity of the current changes

  4. Polarity of the current remains the same
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Electrochemical cells produce DC.

AC is generated by a generator.

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

What is not a characteristic of alternating current?

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Characteristics of alternating current :

1. Periodic in nature
2. Time period does not change
3. Average value is zero.
Multiple choice ac and dc ac vs dc electro-magnetism effects of electric current physics

Why is AC preferred over DC for transmission of electrical power

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. > S
  2. $\approx$ S

  3. < S
  4. $\approx$ G
Reveal answer Fill a bubble to check yourself
A Correct answer
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.                                      

Multiple choice 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

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

  1. Prevent rusting

  2. Make handling easier

  3. Prevent shocks & short circuits

  4. Make them look beautiful
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice 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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

Multiple choice 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

All wires used in electric circuits should be covered with

  1. a coloured material

  2. an insulating material

  3. a conducting material

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
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.