Please select a subject first
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A transformer converts 240 V AC to 60 V AC. The secondary has 75 turns. The number of turns in primary are _______.
(A) 600
(B) 500
(C) 400
(D) 300
Concept: Transformers
Define coefficient of mutual induction.
Concept: Inductance >> Mutual Inductance
Explain the phenomenon of mutual induction.
Concept: Inductance >> Mutual Inductance
Write the SI unit and dimention of of co-efficient of self induction
Concept: Inductance >> Self Inductance
Define the capacitance of a capacitor and its SI unit.
Concept: The Parallel Plate Capacitor
A parallel plate air condenser has a capacity of 20µF. What will be a new capacity if:
1) the distance between the two plates is doubled?
2) a marble slab of dielectric constant 8 is introduced between the two plates?
Concept: The Parallel Plate Capacitor
Answer the following:
State the principles of the electric motor and electric generator.
Concept: Electromagnetic Induction
Choose the correct option:
A conductor rod of length (l) is moving with velocity (v) in a direction normal to a uniform magnetic field (B). What will be the magnitude of induced emf produced between the ends of the moving conductor?
Concept: Electromagnetic Induction
What is the energy required to build up current of 1A in an inductor of 20 mH?
Concept: Energy Stored in a Magnetic Field
In a Faraday disc dynamo, a metal disc of radius R rotates with an angular velocity ω about an axis perpendicular to the plane of the disc and passing through its center. The disc is placed in a magnetic field B acting perpendicular to the plane of the disc. Determine the induced emf between the rim and the axis of the disc.
Concept: Induced Emf in a Stationary Coil in a Changing Magnetic Field
A horizontal wire 20 m long extending from east to west is falling with a velocity of 10 m/s normal to the Earth’s magnetic field of 0.5 × 10−4 T. What is the value of induced emf in the wire?
Concept: Induced Emf in a Stationary Coil in a Changing Magnetic Field
A search coil having 2000 turns with area 1.5 cm2 is placed in a magnetic field of 0.60 T. The coil is moved rapidly out of the field in a time of 0.2 s. Calculate the induced emf in the search coil.
Concept: Induced Emf in a Stationary Coil in a Changing Magnetic Field
An aircraft of wing span of 50 m flies horizontally in the Earth's magnetic field of 6 x 10-5 T at a speed of 400 m/s. Calculate the emf generated between the tips of the wings of the aircraft.
Concept: Motional Electromotive Force (e.m.f.)
A circular coil of 100 turns with a cross-sectional area of 1 m2 is kept with its plane perpendicular to the magnetic field of 1 T. The magnetic flux linkage is ______.
Concept: Transformers
In which of the following devices, the eddy current is not used ______
Concept: Eddy Currents or Foucault Currents
The role of inductance is equivalent to ______
Concept: Induction and Energy Transfer
In the expression e = –dΦ/dt, the -ve sign signifies ______
Concept: Induced Emf in a Stationary Coil in a Changing Magnetic Field
Distinguish between Step up and Step Down Transformer.
Concept: Transformers
A plane of a coil of 10 turns is tightly wound around a solenoid of diameter 2 cm having 400 turns per centimeter. The relative permeability of the core is 800. Calculate the inductance of the solenoid.
Concept: Induction and Energy Transfer
