Electromagnetic Induction - Online Test
Q1. electromagnetic induction i.e currents can be induced in coils (Select the best)
Answer : Option C
Explaination / Solution:
for electromagnetic induction magnet and coil both may move but relative motion between must be present
Q2. When a bar magnet is pushed towards the coil connected in series with a galvanometer, the pointer in the galvanometer G
Answer : Option B
Explaination / Solution:
When bar is in motion then flux will changed hence current will be induced.
Q3.
When current carrying coil is moved towards the coil connected in series with a galvanometer, the pointer in the galvanometer G
Answer : Option C
Explaination / Solution:
current induced due to flux changed when C2 is in motion .
Q4. Coils and are stationary. connected in series with a galvanometer while is connected to a battery through a tapping key. If the tapping key is pressed and released the galvaometer
Answer : Option C
Explaination / Solution:
flux will be changed when current in C2 is changing. Hence current will be induced in coil C1.
Q5. Magnetic flux (ΦB) through a surface S is given by
Answer : Option D
Explaination / Solution:
if dS is area of an element of any arbitrary shape and magnetic field at this element is B.
The total magnetic flux through the surface is the sum of the contributions from the individual area elements.
Q6. According to Farady's law
Answer : Option D
Explaination / Solution:
The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit.
Q7. According to Farady's law for a coil having N turns, the total induced emf is given by
Answer : Option C
Explaination / Solution:
The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit.
induced emf for a coil having 1 turns will be
The flux of all the turns will be added up. So the induced emf for a coil having N turns will be
Q8. Coils and are stationary. connected in series with one very small diwali bulb while is connected to a battery .If the connection is suddenly snapped
Answer : Option D
Explaination / Solution:
Flux will be changed due to this current is induced momentarily
Q9. According to Lenz’s law
Answer : Option B
Explaination / Solution:
Direction of an induced emf, or the current, in any circuit is such as to oppose the cause that produce it.
If the direction of the induced current were such as not to oppose then we would be obtaining electrical energy continuously without doing work, which is impossible
Q10. If the polarity of induced emf is such that it tends to produce a current which aids the change in magnetic flux that produced it, which conservation law is violated?
Answer : Option C
Explaination / Solution:
In this case we would be obtaining electrical energy continuously without doing any work.
