MCQ Collection
ECAT MCQs
Practice ECAT questions with answers and explanations.
Choose an option to check your answer.
Correct Answer: D. 400
Explanation:
One half-life reduces the undecayed population by half.
800/2 = 400 nuclei.
Choose an option to check your answer.
Correct Answer: A. 60 C
Explanation:
Charge is Q=It.
Q=3×20 = 60 C.
Choose an option to check your answer.
Correct Answer: B. 4 A
Explanation:
Current is charge divided by time.
I=120/30 = 4 A.
Choose an option to check your answer.
Correct Answer: C. 3 A
Explanation:
Ohm's law gives I=V/R.
I=12/4 = 3 A.
Choose an option to check your answer.
Correct Answer: D. 30 V
Explanation:
Use V=IR.
V=2×15 = 30 V.
Choose an option to check your answer.
Correct Answer: A. 10 Ω
Explanation:
Series resistances add directly.
R=3+7 = 10 Ω.
Choose an option to check your answer.
Correct Answer: B. 2 Ω
Explanation:
For two parallel resistors, R=R1R2/(R1+R2).
R=18/9 = 2 Ω.
Choose an option to check your answer.
Correct Answer: C. A force perpendicular to both velocity and magnetic field
Explanation:
Magnetic force is qvB sinθ in magnitude.
It changes direction of motion but does no work on the charge.
Choose an option to check your answer.
Correct Answer: C. 2 Ω
Explanation:
Equal parallel resistors have equivalent R/n.
6/3 = 2 Ω.
Choose an option to check your answer.
Correct Answer: D. Production of an emf by changing magnetic flux
Explanation:
Faraday's law links induced emf to the rate of magnetic-flux change.
Relative motion or changing current can produce induction.
Choose an option to check your answer.
Correct Answer: D. 1200 W
Explanation:
Electrical power is P=VI.
P=240×5 = 1200 W.
Choose an option to check your answer.
Correct Answer: A. Induced current opposes the change that produces it
Explanation:
Lenz's law gives the direction of induced current.
It reflects conservation of energy.
