Alternating Current(12th Grade > Physics ) Questions and Answers
Explanation:-
Answer: Option B. -> The glow increases:
B
The glow increases because, when frequency vis increased, the capacitive reactance Xc=12πvCdecreases and hence the current through the bulb increases which will lead to increase in glow
Explanation:-
Answer: Option A. -> 2A:
A
Given XL=XC=5Ω this is the condition of resonance. Since VL=VCnet voltage across L and C combination will be zero.
Voltage drop across the resistance = 110v. Thus current flowing though Ammeter reading =110v55=2A.
Explanation:-
Answer: Option D. -> n> nr:
D
The current will lag behind the voltage when reactance of inductance is more than the reactance of condenser. Thus, ωL>1wCor ω>1√LC or n>12π√LCor n>nrwhere nr= resonant frequency
Question 6. Following figure shows an ac generator connected to a "block box" through a pair of terminals. The box contains possible R, L, C or their combination, whose elements and arrangements are not known to us. Measurements outside the box reveals that e = 75 sin (sin ωt) volt, i = 1.5 sin (ωt + 45∘) amp then, the wrong statement is
Explanation:-
Answer: Option B. -> There must be no inductor in the box:
B
Since voltage is lagging behind the current, so there must be no inductor in the box.
Explanation:-
Answer: Option B. -> The voltage leads the current by Π2:
B
At t = 0, phase of the voltage is zero, while phase of the current is −π2 i.e., voltage leads by π2