40 Questions
What is the phenomenon of inducing an opposing emf in the secondary coil due to a change in current in the primary coil called?
Mutual induction
What is the constant of proportionality between the magnetic flux linked with the secondary coil and the current passing through the primary coil?
Coefficient of mutual induction
What is the SI unit of mutual inductance?
Weber
What is the dependence of the magnetic flux linked with the secondary coil on the current passing through the primary coil?
Directly proportional
What is the induced emf in the secondary coil dependent on?
Rate of change of current
What is the definition of 1 henry?
Induced emf of 1 V with a rate of change of current of 1 A/s
What is the relationship between the magnetic flux linked with the secondary coil and the number of turns of the coil?
Directly proportional
What is the unit of mutual inductance in terms of Vs/A?
VsA^-1
What is the time taken for one complete cycle in the given problem?
0.040 s
What is the value of omega (ω) in the given problem?
157 rad/s
What is the emf (ε₀) when the coil reaches its peak value?
63.6 V
What is the area of the coil in problem 44?
0.04 m²
What is the frequency of the AC generator in problem 45?
30 rps
What is the maximum current drawn from the generator in problem 45?
3 A
What is the magnetic field strength in problem 46?
0.212 T
What is the angular frequency (ω) in problem 46?
2π x 60 rad/s
What happens when the key (K) is pressed in Experiment 2?
The galvanometer shows a deflection.
What conclusion can be drawn from the coil-coil experiment (One loop is stationary)?
Relative motion between the two coils induces emf.
According to Faraday's First Law, what induces an emf in a circuit?
Changing magnetic flux
What does the galvanometer show when the key is kept open or closed in Experiment 2?
No deflection
Which phenomena are the experiments demonstrating?
Electromagnetic induction
What is directly proportional to the induced emf according to Faraday's Second Law?
Negative rate of change magnetic flux
How is the galvanometer connected in Experiment 3?
To the stationary loop
According to Faraday’s First Law, what does the amount of induced emf depend upon?
The rate of change of magnetic flux
What principle is a transformer based upon?
Mutual inductance
Why is a transformer core laminated?
To reduce energy losses due to eddy currents
Which type of source does a transformer work with?
Alternating current (AC)
What is the function of the primary coil in a transformer?
It is connected to the AC voltage supply
Why does a transformer not work with a DC source?
DC produces a steady current with no changing magnetic flux
What happens in a step-up transformer?
Voltage is stepped up from low to high
In a transformer, why is the core made of soft iron?
To increase magnetic permeability and reduce eddy currents
In power transmission, why is a step-up transformer preferred over a step-down transformer for long distances?
It reduces the current and hence power losses
What is the change in flux when the initial flux is 2 Wb and the final flux is 8 Wb?
6 Wb
What is the formula used to calculate the induced emf?
$e = N \frac{d\phi}{dt}$
What is the magnitude of the emf induced in a 560-turn coil with an area of $0.065 m \times 0.065 m$, placed in a magnetic field of 1.2 T, when rotated 90 degrees in 0.2 ms?
$1.42 \times 10^4 V$
If the magnetic flux through a coil of 50 turns decreases from $3 \times 10^{-2}$ Wb to 0 in 20 ms, what is the induced emf?
75 V
What is the initial magnetic flux through a coil with 560 turns, an area of $0.065 m \times 0.065 m$, and a magnetic field strength of 1.2 T?
$5.07 \times 10^{-3} Wb$
What is the current in a coil with a resistance of 100 ohms if the induced emf is 75 V?
0.75 A
A coil initially oriented such that its axis coincides with the magnetic field direction is then rotated 90 degrees. What is the final flux if the magnetic field is 1.2 T and the area of the coil is $0.065 m \times 0.065 m$?
0 Wb
What is the charge in a coil if the current is 0.75 A and the time is 20 ms?
$1.5 \times 10^{-2} C$
This experiment demonstrates the phenomenon of electromagnetic induction, where two coils are placed close to each other and connected to a battery and a galvanometer, showing deflections when the key is pressed and released.
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