electromagnetic induction

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Created on By buzzerkings

Electromagnetic Induction

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If a stationary bar magnet is placed near a coil at rest so maximum lines of force passes through the coil, the galvanometer shows:

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Transformer is a device which steps up or steps down the input:

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 The domestic electricity supply has a frequency of:

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 in transmission from grid station, power losses are minimized by:

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The function of main transformer is to convert:

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The phenomenon used for producing emf in coil of generator is;

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The phenomenon of mutual induction is practically used is

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A transformer changes 12V to 18000 V and there are 6000 turns in the secondary coil. The number of turns in the primary coil are:

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The number of turns in the primary and secondary coil of a step up transformer are 200 and 500 respectively. If the power in the input is 100 Watt and current 1A then the output power and current will respectively

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A step-up transformer

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A step-down transformer is used on a 1000 V line to deliver 20 A at 120 V at the secondary coll. If the efficiency of the transformer is 80% the current drawn from the line is

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The efficiency of transformer is very high because 

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The ratio of secondary to the primary turns in a transformer is 3: 2. If the power output be P, then the input power neglecting all loses must be equal to

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Primary and secondary coils of a transformer have 50 and 200 turns respectively. When primary is connected to 9-volt battery secondary voltage is

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To improve efficiency of transformer the flux coupling between primary & secondary coils should be

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 If turns in primary = 50, secondary = 200, primary voltage = 120V, primary current 3A, then output power will be about

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A step-down transformer, transforms 220 voll to 11 volt. If the current in primary and secondary coil are 5A and 90 A respectively, efficiency of transformer is 

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The loss of power in transformer is due to 

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 Laminated core in a transformer is used to reduce

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_____is the energy expended to magnetize and demagnetize the core material in each cycle of the A.C.

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In a transformer heat is produced due to eddy current in 

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 In step up transformer, voltage in the secondary increases and power in secondary

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A transformer is used to light a 100 W and 110 V lamp from 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is approximately.

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A transformer is used to

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The turn ratio of a transformer is 2:3. If the current through primary is 3A, then current through load resistance is

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The voltage in the primary and the secondary colls of a step-up transformer are 200 V and 4 kV respectively. If the current in the primary is 1 ampere then the current in the secondary coil will be

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 Which of the remain constant in a transformer?

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Which quantity is increased in step-down transformer?

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The armature of a generator consists of a flat square coil of side 4 cm and 200 turns. The coil rotates in a magnetic field of 0.75T. The angular speed so that a maximum emf of 1.6V is generated is

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The principle of an electric generator is based on

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The output of an a.c. generator has a

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 An electric generator is a device that transforms____ energy into electrical energy

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When a coil of cross-sectional area A and number of turns N is rotated in a uniform magnetic field B with angular velocity ω, then the maximum emf induced in the coil will be

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Lenz's law is a manifestation of the conservation of 

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A magnet falls with its S-pole along the axis of ring. The current generated is___ .... And acceleration is

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 In a circuit with a coil of resistance 2 ohms, the magnetic flux changes from 2.0 Wb to 10.0 Wb in 0.2 second. The charge that flows in the coil during this time is

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 A coil having 500 square loops each of side 10 cm is placed normal to a magnetic induction which increases at the rate of 1.0 tesla/second. The induced e.m.f. in volts is

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The e.m.f. induced in a coil is ......... the rate of change in flux linkages.

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Q.7 In the equation ε=-Nⲫ/Δt the negative sign indicates that 

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A metallic circular ring is suspended by a string and is kept in a vertical plane. When a magnet is approached towards the ring then it will

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 The direction of induced current in a coil or circuit is such that it opposes every cause of its production. This law is given by

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 Relative motion between a_____ and a conducting coil produces current in the coil

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Which one of the following does not affect the magnitude of the induced emf in electromagnetic induction?

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Which of the following will not generate emf? 

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