A resistor of 5 Ω has 6 V across it. Enter the current in amperes.
Correct Answer: 1.2
Explanation:
Ohm’s law gives I=V/R=6/5=1.200 A.
MCQ Collection
China MCQs
Practice China questions with answers and explanations.
Practice context 8: Which statement correctly defines radioactive half-life?
Choose an option to check your answer.
Correct Answer: C. The half-life is the time for the number of undecayed nuclei to fall to half its initial value
Explanation:
Half-life is a characteristic decay time at which the undecayed population becomes one half.
An object travels 280 m in 11 s at constant speed. Enter its speed in m/s.
Correct Answer: 25.45
Explanation:
Speed=distance/time=280/11=25.45 m/s.
A net force accelerates a 3 kg mass at 3 m/s². Enter the force in newtons.
Correct Answer: 9
Explanation:
Newton’s second law gives F=ma=3×3=9 N.
Enter the kinetic energy of a 5 kg object moving at 3 m/s.
Correct Answer: 22.5
Explanation:
K=½mv²=½×5×3²=22.5 J.
A resistor of 4 Ω has 15 V across it. Enter the current in amperes.
Correct Answer: 3.75
Explanation:
Ohm’s law gives I=V/R=15/4=3.750 A.
A wave has frequency 3 Hz and wavelength 4 m. Enter its speed.
Correct Answer: 12
Explanation:
Wave speed v=fλ=3×4=12 m/s.
Practice context 9: Which statement correctly expresses conservation of momentum?
Choose an option to check your answer.
Correct Answer: B. The total momentum of an isolated system remains constant
Explanation:
In an isolated system, internal forces occur in equal and opposite pairs, so total momentum is constant.
Practice context 9: For a transverse wave, how is the oscillation direction related to propagation?
Choose an option to check your answer.
Correct Answer: C. It is perpendicular to the direction of wave propagation
Explanation:
A transverse wave oscillates perpendicular to the direction in which the wave travels.
An object travels 260 m in 10 s at constant speed. Enter its speed in m/s.
Correct Answer: 26
Explanation:
Speed=distance/time=260/10=26.00 m/s.
A net force accelerates a 2 kg mass at 2 m/s². Enter the force in newtons.
Correct Answer: 4
Explanation:
Newton’s second law gives F=ma=2×2=4 N.
Enter the kinetic energy of a 4 kg object moving at 2 m/s.
Correct Answer: 8
Explanation:
K=½mv²=½×4×2²=8.0 J.