NEET Physics Alternating Current Voltage and Power MCQs Set A

Question: Alternating current cannot be measured by D.C. ammeter, because*
a) average value of A. C for complete cycle is zero
b) A. C. cannot pass through D.C. ammeter
c) A. C. changes its direction
d) A. C. is virtual
Answer: average value of A. C for complete cycle is zero

Question: The peak value of the a.c. current flowing through a resistor is given by
a)

b)

c)

d) None of these
Answer:

Question: A.C. power is transmitted from a power house at a high voltage as
a) it is more economical due to less power loss
b) power cannot be transmitted at low voltages
c) a precaution against theft of transmission lines
d) the rate of transmission is faster at high voltages
Answer: it is more economical due to less power loss

Question:  The ratio of mean value over half cycle to r.m.s. value of A.C. is
a)

b)

c)

d) None of these
Answer:

Question: The average power dissipated in a pure inductance is
a) zero

b)

c)

d)

Answer: zero

Question: If the frequency of an A.C. is made 4 times of its initial value, the inductive reactance will
a) be 4 times
b) be 2 times
c) be half
d) remain the same
Answer: be 4 times

Question: When an ac voltage of 220 V is applied to the capacitor C, then
a) power delivered to the capacitor per cycle is zero
b) the charge on the plate is not in phase with the applied votage.
c) the current is in phase with the applied voltage
d) the maximum voltage between plates is 220 V.
Answer:  power delivered to the capacitor per cycle is zero

Question: In the case of an inductor
a)

b)

c)

d) None of these

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:

a)

b)

c)

d)

Answer:

Question:
Assertion : Average value of ac over a complete cycle is always zero.
Reason: Average value of ac is always defined over half cycle.
a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
b) Assertion is correct, reason is incorrect
c) Assertion is incorrect, reason is correct.
d) Assertion is correct, reason is correct; reason is a correct explanation for assertion
Answer: Assertion is correct, reason is correct; reason is not a correct explanation for assertion

Question:

a)

b)

c)

d)

Answer:

Question: The r.m.s value of an a.c. of 50 Hz is 10 amp. The time taken by the alternating current in reaching from zero to maximum value and the peak value of current will be

a)

b)

c)

d) None of these

Answer:

Question:

a) 2.828 A
b) 1.732 A
c) Both
d) None of these
Answer: 2.828 A

Question:

a) 20 mA
b) 200 mA
c) 100 mA
d) 10 mA
Answer: 20 mA

Question:

a) zero
b)

c)

d) None of these
Answer: zero

Question:

a) 50 times
b) 30 times
c) 100 times
d) 25 times
Answer: 50 times

Question:

a)

b)

c)

d) None of these
Answer:

Question:

a)

b)

c) Both
d) None of these
Answer:

Question:

a) – 10 cos (500t)
b) – 10 sin (500t)
c) 10 cos (500 t)
d) 10 sin (500t)
Answer: – 10 cos (500t)