Tag: ac and dc

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Questions Related to ac and dc

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.