Electromagnetic Induction & Alternating Currents (NEET Physics): Questions 72  76 of 121
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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. 


Question number: 75
» Electromagnetic Induction & Alternating Currents » Self and Mutual Inductance
Question
A small coil of N _{1} turns, l _{1} length is tightly wound over the center of a long solenoid of length l _{2}, area of crosssection A and number of turns N _{2}. If a current I flows in the small coil, then the flux through the long solenoid is,
Choices
Choice (4)  Response  

a. 


b. 


c.  zero 

d. 


Question number: 76
» Electromagnetic Induction & Alternating Currents » AC Generator and Transformer
Question
A 50 Hz a. c. current of crest value 1A flows through the primary of a transformer. If the mutual inductance between the primary and secondary be 1.5 H, the crest voltage induced in secondary is
Choices
Choice (4)  Response  

a.  471 V 

b.  300 V 

c.  150 V 

d.  75 V 
