Electromagnetic Induction & Alternating Currents (NEET Physics): Questions 67 - 71 of 121

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Question number: 67

» Electromagnetic Induction & Alternating Currents » Peak and RMS Value of AC

MCQ▾

Question

If instantaneous current is given by i=4cos(ωt+ϕ) amperes, then the r. m. s value of current is

Choices

Choice (4) Response

a.

4 ampere

b.

22ampere

c.

zero ampere

d.

42ampere

Question number: 68

» Electromagnetic Induction & Alternating Currents » Alternating Currents

Assertion-Reason▾

Assertion (Ꭺ)

An alternating current does not show any magnetic effect.

Reason (Ꭱ)

Alternating current varies with time.

Choices

Choice (4) Response

a.

Ꭺ is false but Ꭱ is true

b.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

c.

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

d.

Both Ꭺ and Ꭱ are false

Question number: 69

» Electromagnetic Induction & Alternating Currents » Peak and RMS Value of AC

MCQ▾

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

MCQ▾

Question

In an ac circuit I=100sin200πt . The time required for the current to achieve its peak value will be

Choices

Choice (4) Response

a.

1100sec

b.

1300sec

c.

1200sec

d.

1400sec

Question number: 71

» Electromagnetic Induction & Alternating Currents » Peak and RMS Value of AC

MCQ▾

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

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