30 Questions
What is the formula for mutual inductance M in terms of the coefficient of permeability μ0, number of turns N1 and N2, and area of cross-section A?
M = μ0 N1 N2 A / l
What is the effect on mutual inductance M when the distance d between the two coils increases?
M decreases
What is the coefficient of coupling k in terms of mutual inductance M, self-inductance L1, and self-inductance L2?
k = M / sqrt(L1 L2)
What is the expression for the flux linked with the coil at any time t?
φ = NBAcosωt
What is the net inductance LS when two magnetically coupled coils are connected in series and are far from each other?
LS = L1 + L2 + 2M
What is the condition for maximum mutual inductance between two coils?
The coils are in close proximity to each other
What is the coefficient of self-induction of a coil equal to?
The flux linked with the coil when the current in it is 1 amp
What is the unit of coefficient of self-induction in the SI system?
Ohm × sec
What is the expression for the induced emf in a coil?
e = -NBAωsinωt
What is the relation between the number of flux linkages with the coil and the current i?
Nφ ∝ i
What is the dimensional formula for self inductance (L)?
[ML2T–2A–2]
What is the magnetic potential energy of an inductor?
U = (Li)i / 2
What is the phenomenon where the magnetic flux linked with a neighbouring coil or circuit changes when the current passing through a coil or circuit changes?
Mutual induction
What is the unit of self inductance (L)?
Henry (H)
What is the formula for self inductance (L) for a coaxial cylinder?
L = μ0 * log(e) / (2 * π * r1)
What is the purpose of the hair springs in the magnet mount?
To hold the magnet in place
What is the direction of the force on AB in the given figure?
Perpendicular to the plane of the paper and pointing inwards
What is the effect of the back emf in a motor?
It decreases the speed of the motor
What is the purpose of the split ring commutators in the motor?
To reverse the direction of the current in the coil
What is the relationship between the back emf and the angular velocity of the armature?
e ∝ ω
What is the direction of motion of the loop if the cause of induced emf is relative motion?
In the direction of motion of the magnet
What is the nature of the induced electric field?
Non-conservative and non-electrostatic
What is the shape of the field lines of the induced electric field?
Concentric circular closed curves
What is the relationship between the induced emf and the induced electric field?
Induced emf is directly proportional to the induced electric field
What is the direction of the repulsive force between the magnet and the loop if the loop is free to move?
Anticlockwise direction
What happens when the speed of a magnet increases in a freely falling conducting rod?
Induced emf increases, but charge remains the same
What is the relationship between the inductance at the ends of a solenoid and at its centre?
Inductance at the ends is half that at the centre
Why is it difficult to obtain a pure resistor?
Because it always has some inductance and capacitance
What is the condition for no flux cutting to occur?
When two vectors are parallel to each other
What is the vector form of motional emf?
e = (v × B) ⋅ l
This quiz covers the concepts of inductance, self-inductance, and magnetic field. It includes dimensional formulas, dependence of self-inductance, and formulas for inductance in different scenarios.
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