Electromagnetic Induction & Alternating Currents (NEET (NTA)National Eligibility cum Entrance Test (Medical) Physics): Questions 69  74 of 124
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Question number: 69
» Electromagnetic Induction & Alternating Currents » Peak and RMS Value of AC
Question
A resistance of 20Ω is connected to a source of an alternating potential V = 220 sin (100πt). The time taken by the current to change from its peak value to r. m. s value is,
Choices
Choice (4)  Response  

a.  0.25 sec 

b.  0.2 sec 

c.  2.5 x 10 ^{3} sec 

d.  25 x 10 ^{3} sec 

Question number: 70
» Electromagnetic Induction & Alternating Currents » Alternating Currents
Question
In an ac circuit . The time required for the current to achieve its peak value will be
Choices
Choice (4)  Response  

a. 


b. 


c. 


d. 


Question number: 71
» Electromagnetic Induction & Alternating Currents » Peak and RMS Value of AC
Question
In a circuit, the value of alternating current is measured by hot wire ammeter as 10 ampere. Its peak value will be
Choices
Choice (4)  Response  

a.  20 A 

b.  14.14 A 

c.  7.07 A 

d.  10 A 

Question number: 72
» Electromagnetic Induction & Alternating Currents » Peak and RMS Value of AC
Question
The peak value of an alternating e. m. f. E given by E = E _{0} cos t is 10 volts and its frequency is 50 Hz. At time , the instantaneous e. m. f. is
Choices
Choice (4)  Response  

a.  1 V 

b.  10 V 

c.  5 V 

d. 


Question number: 73
» Electromagnetic Induction & Alternating Currents » AC Generator and Transformer
Question
A transformer has turn ratio 100: 1. If secondary coil has 4 amp current then current in primary coil is
Choices
Choice (4)  Response  

a.  4 A 

b.  0.04 A 

c.  400 A 

d.  0.4 A 

Question number: 74
» Electromagnetic Induction & Alternating Currents » Reactance and Impedance
Question
An inductor (L = 100 mH), a resistor (R = 100Ω) and a battery (E = 100 V) are initially connected in series as shown in the figure. After a long time the battery is disconnected after short circuiting the points A and B. The current in the circuit 1 ms after the short circuit is
Choices
Choice (4)  Response  

a.  1 A 

b.  0.1 A 

c.  e A 

d. 

