Previous Year Physics Question Papers (with solutions) of Kerala State Syllabus of Higher Secondary Examinations. Chapter Name: ELECTROMAGNETIC INDUCTION

Self-inductance of a coil plays the role of inertia in a circuit.
a) The SI unit of self-inductance is -----
b) Current in a circuit falls from 5A to IA in 0.1 second. If an average EMF of 200 volts is induced, find the self- inductance of the coil.

Sometimes when we switch off electrical equipment, a spark is seen within the switch. This is explained on the basis of electromagnetic induction.
a) What is self-induction?
a) Current is a circuit falls from 5A to 0A in 0.1S. If an average emf of 200V is induced, determine the self-inductance of the circuit.

The phenomenon in which electric current is generated by varying magnetic field is called electromagnetic induction.
a) Which law helps to detect the direction of induced current? State the law.
b) Explain what are eddy currents?
c) Write any two uses of eddy currents.

Match the following quantities using the analogy between mechanical and electrical quantities.

i) Mass (M)	Charge(q)
ii) Force constant (k)	Resistance (R)
iii) Displacement (x)	Max. charge stored (q)
vi) Velocity (v)	Inductance (L)
v) Amplitude of forced oscillation (A)	Reciprocal of capacitance (1/c)
vi) Damping constant (b)	Current (i)

The generation of e.m.f when the magnetic flux associated with a coil changes is known as electromagnetic induction
a) Mention the factors on which the self-inductance of a solenoid depends
b) Calculate the energy stored in an inductor of inductance 50 mH when a current of 2 A is passing through it
c) Two identical loops one of copper and other of aluminium are rotated with same speed in the same magnetic field. In which case the
i) Induced e.m.f ii) Induced current will be more and why?

For many purposes, it is necessary to change an alternating voltage from one value to another. This is done with a transformer
a) The basic principle behind a transformer is ..........................
b) Give an expression for the voltage and current in a transformer

When magnetic flux linked with a coil changes an emf is induced in the circuit
(A) State Faradays law of electromagnetic induction
(B) Mention the physical significance of Lenzs law with an example
(C) When an electric appliance is switched off, sparking occurs. Why?

(a) The core of a transformer has the following properties:
(i) core is laminated (ii) hysteresis loop is narrow
Explain the significance of each property
(b) what is meant by resonance in an LCR circuit?

(a) The electrical analog of mass is
(i) diode (ii) capacitance (iii) Inductance (iv) resistance
(b) A 2m long solenoid having diameter 6 cm and 2000 turns has a secondary of 500 turns wound closely near its mid – point. Calculate the mutual inductance between the two coils

(a) Derive an expression for self inductance of a solenoid.
(b) What do you mean by eddy current ? Write any two applications of it.

Two long co-axial solenoids of same length are shown:
(a) Define mutual inductance of the pair of coils.
(b) Derive an expression for mutual inductance of two co-axial solenoids.
(c) Write the dimension of mutual inductance.

(a) When current through a coil changes an e.m.f. is induced in the neighboring coil. This is called mutual induction
(b)
Derivation
N ₁ Φ₁ = M ₁₂ I ₂
N ₁ Φ₁ = ( n₁ L) (π r₁²) ( μ₀ n₂ I₂ )
M ₂₁ = M = μ ₀ n ₁ n ₂ π r₁²L
(c) M L² T^-2 A^-2

Coefficient of mutual inductance of two coils is 1 H. Current in one of the coils is increased from 4 to 5 A in 1 ms. What average emf will be induced in the other coil ?
(a) 1000 V (b) 2000 V (c) 100 V (d) 200 V

(a) State Faraday’s law of electromagnetic induction.
(b) How does the magnetic energy stored in an inductor and electrostatic energy stored in a capacitor related to their respective field strengths ?