The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?

   
(a) (b)
   
(c) (d)

Choose the correct option from the given ones:

1. (a) and (d)
2. (a), (b), (c), and (d)
3. (a) and (b)
4.  only (a)

Subtopic:  AC vs DC |
 79%
Level 2: 60%+
NEET - 2019
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In the diagram, two sinusoidal voltages of the same frequency are shown. What is the frequency and the phase relationship between the voltages?
        

Frequency in Hz Phase lead of \(N\) over \(M\) in radians
1. \(0.4\) \(-\pi/4\)
2. \(2.5\) \(-\pi/2\)
3. \(2.5\) \(+\pi/2\)
4. \(2.5\) \(-\pi/4\)
Subtopic:  AC vs DC |
 68%
Level 2: 60%+
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An AC ammeter is used to measure the current in a circuit. When a given direct current passes through the circuit, the AC ammeter reads \(6~\text A.\) When another alternating current passes through the circuit, the AC ammeter reads \(8~\text A.\) Then the reading of this ammeter if DC and AC flow through the circuit simultaneously is:
1. \(10 \sqrt{2}~\text A\) 
2. \(14~\text A\) 
3. \(10~\text A\) 
4. \(15~\text A\) 

Subtopic:  AC vs DC |
 67%
Level 2: 60%+
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Alternating current cannot be measured by a DC ammeter because:
1. AC cannot pass through DC Ammeter.
2. AC changes direction.
3. Average value of current for the complete cycle is zero.
4. DC Ammeter will get damaged.
Subtopic:  AC vs DC |
 65%
Level 2: 60%+
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In a heating arrangement, an alternating current having a peak value of \(28~\text{A}\) is used. To produce the same heat energy, if direct current is used to produce the same amount of heat, then its magnitude will be:
1. about \(14~\text{A}\)  2. about \(28~\text{A}\)
3. about \(20~\text{A}\) 4. cannot say
Subtopic:  AC vs DC |
 57%
Level 3: 35%-60%
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