Question
You are given the following current- time graphs from two different sources:


Now, answer the following questions:
  1. Name the type of current in two cases. 
  2. Identify any one source for each type of these currents. 
  3. What is the frequency of current in case (b) in India?
Use above graphs to write two differences between the current in two cases.

Answer

In graph (a) current is constant and in graph (b) current is different.
1. Source of (a) is battery and source of (b) is AC generator.
2. 50Hz frequency of current in case b.
3.
Alternating currentDirect current
1.
Both the magnitude and direction of current varies within equal intervals of time.
Direction of current does not vary with time and remains constant.
2.
The frequency of ac is 50Hz or 60Hz depending upon the country.
The frequency for direct current is zero.

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