Electromagnetic Induction & Alternating Currents (NEET Physics): Questions 43 - 46 of 121

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Question number: 43

» Electromagnetic Induction & Alternating Currents » Alternating Currents

Assertion-Reason▾

Assertion (Ꭺ)

The alternating current lags behind the emf by a phase angle of π2 , when ac flows through an inductor.

Reason (Ꭱ)

The inductive reactance increases as the frequency of ac source decreases.

Choices

Choice (4) Response

a.

Both Ꭺ and Ꭱ are false

b.

Ꭺ is true but Ꭱ is false

c.

Ꭺ is false but Ꭱ is true

d.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

Question number: 44

» Electromagnetic Induction & Alternating Currents » AC Generator and Transformer

MCQ▾

Question

Large transformer, when used for some time, become hot and are cooled by circulating oil. The heating of transformer is due to

(1) Heating effect of current

(2) Hysteresis loss

(3) Chemical effect of current

(4) Magnetic effect of current

Select the correct answers and mark it according to the following

Choices

Choice (4) Response

a.

1, 2 and 3 are correct

b.

2 and 4 are correct

c.

1 and 2 are correct

d.

1 and 3 are correct

Question number: 45

» Electromagnetic Induction & Alternating Currents » Reactance and Impedance

MCQ▾

Question

An inductive circuit contains resistance of 10Ω and an inductance of 20 H. If an ac voltage of 120 V and frequency 60 Hz is applied to this circuit, the current would be nearly

Choices

Choice (4) Response

a.

0.80 A

b.

0.016 A

c.

0.32 A

d.

0.48 A

Question number: 46

» Electromagnetic Induction & Alternating Currents » Faraday's Law

MCQ▾

Question

The magnetic flux passing perpendicular to the plane of the coil and directed into the paper is varying according to the relation Φ=3t2+2t+3 , where is in milli-weber and t is in second. Then the magnitude of emf induced in the loop when t = 2 second is-

Choices

Choice (4) Response

a.

-6 mV

b.

31 mV

c.

19 mV

d.

-14 mV

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