Alternating Current
7 free MDCAT Physics MCQs on Alternating Current (PM&DC syllabus), each with the answer, an explanation and the textbook line it comes from. Tap to check, no sign-up.
Tap an answer to check it · 7 questions
-
Question 1
The steady direct current that produces the same heat in a resistor as an alternating current in the same time is the AC's:Show answer and explanation
Answer: B) R.m.s value
Irms = I0 / sqrt 2. Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 120.
-
Question 2
The opposition that a capacitor presents to alternating current is known as its:Show answer and explanation
Answer: D) Capacitive reactance
XC = 1 / (2 pi f C). Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 117.
-
Question 3
The combined effect of resistance and reactance in an AC circuit is called:Show answer and explanation
Answer: A) Impedance
Z = sqrt(R^2 + X^2), measured in ohms. Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 118.
-
Question 4
In a pure capacitor connected to AC, the voltage:Show answer and explanation
Answer: C) Lags the current by 90 degrees
Remembered by 'ELI the ICE man'. Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 117.
-
Question 5
For direct current (f = 0), the capacitive reactance of a capacitor is:Show answer and explanation
Answer: B) Infinite
So a capacitor blocks DC but passes AC. Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 117.
-
Question 6
The inductive reactance of a coil depends on the:Show answer and explanation
Answer: C) Frequency of the AC
XL = 2 pi f L; it is zero for DC. Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 116.
-
Question 7
In an RL series AC circuit, the current lags the applied voltage by an angle:Show answer and explanation
Answer: A) Less than 90 degrees
It depends on the values of VR and VL. Source: 12 Physics Book FBISE (MaryamNotes.pk), p. 118.
Want a full Alternating Current test?
AXESIO Prep writes new questions on any topic at your level, times you like the real exam and shows exactly what to revise. Free to start.