physics : class12 Relative Motion : Induced Current : Electromagnetic Induction and Alternating Currents MCQ Questions and Answers
Practice important
Relative Motion
MCQ questions and answers.
Page 1
of
1
|
10
MCQ Questions
1. A bar magnet is moved toward a stationary coil. What happens in the coil?
A.
An induced current is produced
B.
No current is produced because the coil is stationary
C.
The coil becomes permanently charged
D.
The magnetic field of the magnet becomes zero
Correct Answer:
An induced current is produced
Explanation:
The motion of the magnet relative to the coil changes the magnetic flux through the coil, producing an induced current.
2. A magnet and a coil move together with the same velocity in the same direction. What is the induced current in the coil?
A.
Maximum current
B.
Zero current
C.
Alternating current
D.
A current independent of their velocities
Correct Answer:
Zero current
Explanation:
Since the magnet and coil have no relative motion, the magnetic flux through the coil does not change, so no induced current is produced.
3. A magnet is moved faster toward a coil. Compared with slower motion, the induced current is generally:
A.
Smaller
B.
Larger
C.
Always zero
D.
Unchanged in every case
Correct Answer:
Larger
Explanation:
Faster relative motion causes the magnetic flux to change more rapidly, resulting in a larger induced emf and, for the same resistance, a larger current.
4. A stationary magnet is approached by a moving coil. Is an induced current produced in the coil?
A.
Yes, because there is relative motion between the magnet and coil
B.
No, because the magnet is stationary
C.
No, because only magnets can produce current
D.
Yes, but only if the coil is not closed
Correct Answer:
Yes, because there is relative motion between the magnet and coil
Explanation:
Induction depends on relative motion and the resulting change in magnetic flux, not on which object is moving.
5. If the direction of motion of a magnet relative to a coil is reversed, what happens to the induced current?
A.
Its direction reverses
B.
Its direction remains unchanged in all cases
C.
It becomes permanently zero
D.
Its direction changes only if the coil is moving
Correct Answer:
Its direction reverses
Explanation:
Reversing the relative motion reverses the change in magnetic flux, so the direction of the induced current also reverses.
6. A straight conducting rod moves parallel to a uniform magnetic field. What is the motional emf due to this motion?
A.
Zero
B.
Maximum
C.
Equal to the resistance of the rod
D.
Independent of the direction of motion
Correct Answer:
Zero
Explanation:
When the rod moves parallel to the magnetic field, its velocity has no component perpendicular to the field, so no motional emf is produced.
7. A magnet moves toward a coil at 2 m/s while the coil moves toward the magnet at 3 m/s. What is their relative speed?
A.
1 m/s
B.
2 m/s
C.
3 m/s
D.
5 m/s
Correct Answer:
5 m/s
Explanation:
When two objects move toward each other, their relative speed is the sum of their speeds: 2 m/s + 3 m/s = 5 m/s.
8. A magnet and a coil move in the same direction with speeds of 6 m/s and 4 m/s, respectively. What is their relative speed?
A.
2 m/s
B.
4 m/s
C.
6 m/s
D.
10 m/s
Correct Answer:
2 m/s
Explanation:
For motion in the same direction, relative speed is the difference between the speeds: 6 m/s − 4 m/s = 2 m/s.
9. A magnet is brought near a coil and then held stationary close to it. When is the induced current present?
A.
Only while the magnet is moving relative to the coil
B.
Continuously while the magnet is held stationary
C.
Only before the magnet reaches the coil
D.
Only when the coil is made of plastic
Correct Answer:
Only while the magnet is moving relative to the coil
Explanation:
Relative motion changes the magnetic flux and induces current. Once the magnet is stationary relative to the coil, the flux becomes constant and the current stops.
10. Two identical coils are approached by identical magnets. The magnet approaches the first coil slowly and the second coil quickly. Which coil has the greater induced current during approach?
A.
The first coil
B.
The second coil
C.
Both always have equal current
D.
Neither coil has induced current
Correct Answer:
The second coil
Explanation:
The faster approach produces a greater rate of change of magnetic flux through the second coil, so it has a greater induced current for the same resistance.
Short Questions and Answers
Practice short questions and answers related to
Relative Motion
.
Short questions are currently unavailable for this page.