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SSLC PHYSICS – Electromagnetic Induction and Electromagnetic Radiation 1. Name the device which converts electrical energy into mechanical energyA. Electric motor.2. What is the principle of DynamoA. A dynamo works on the principle of electromagnetic induction3. In Faraday’s experiment cylinder used to wind copper wire is made of ________A. Armature4. Two equal, parallel, opposite mechanical force acting on a body at two different point to

produce rotation constitutes a _______.A. Couple5. In Fleming’s left hand rule middle finger represents the direction of ______A. Electric current6. In Motor rule fore finger represents the direction of ______A. Magnetic Field7. A current carrying conductor kept in a magnetic field experiences _________A. Mechanical8. Complete the second law of electromagnetic induction.A. “ The induced electromotive force is proportional to the Rate of change of magnetic flux linking

the conductor”9. Definition electromagnetic inductionA. When the magnetic field linked with a circuit changes, An electromotive force will be induced in the

circuit.10. Mention the two factors that influence induced electromotive force.A. Induced emf in a coil increases with the increase in a) The number of turns of the coil b) The rate of

change of magnetic field linking with the coil11. What are the difference between AC Dynamo and DC Dynamo

A.

12. State Faraday’s Laws of Electromagnetic Induction.A. First Law: A changing magnetic field linking a conductor induces an electric motive force in the conductor.Second Law: The induced electromotive force is proportional to the rate of change of magnetic field linking the coil13. State Fleming’s right-hand ruleA. “ Arrange the main finger( Thumb) the forefinger and the central finger of the right hand at right angles to each other such that the forefinger indicates the direction of magnetic field and the main finger

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AC Dynamo DC Dynamo

a. A dynamo that produces an alternating current is called AC dynamo

b. A dynamo that produces a direct current is called DC Dynamo

b. In this type of dynamo the direction of current reverses every half a cycle

b. In this dynamo the current flows in the external circuit in the same direction

indicates the direction of motion of the conductor then the central finger indicates the direction of the current induced.”14. Define Fleming’s Left hand ruleA. Arrange the main finger (Thumb) forefinger and the central finger of the left hand such that they are

mutually perpendicular to one another. If the forefinger indicates the direction of magnetic field and the central finger indicates the direction of electric current then the main finger indicated the direction of mechanical force acting on the conductor.

15. Write the common parts present in the motor and dynamoA. The common parts present in the motor and dynamo are i) Armature ii) Magnetic poles16. Draw a neat diagram of an DC Motor and explain its working. A. Let an electric current be passed through the coil say, in the direction ABCD. Mechanical force acts

on its limbs in opposite directions. By applying motor rule, the direction of mechanical force can be found. The forces, acting on AB and CD from a couple. Therefore, the coil begins to rotates about its axis. When the coil completes the first half of its rotation, Si comes in contact with B2 and S2 comes in contact unit B. Now electric current flows in the coil in the direction

DCBA. Due to the effect of the of the couple formed the coil continues to rotate in the same direction. In this way, a motor converts electrical energy into mechanical energy. Since it works on direct current it is called DC motor.17. Draw a neat diagram of AC Dynamo and explain its construction.A. A dynamo consists of a rectangular coil of insulated copper wire (ABCD) mounted between the

poles N and S of a powerful magnet. The free ends of the copper wire are connected to two copper rings R, and R2. Two carbon brushes B1 and B2 are touching the rings R1 and R2 respectively. These brushes are connected to load in the external circuit. The arrangement of coil along with the rings is called armature.

18. What is armature in the Dynamo.A. The arrangement of coil along with the rings is called armature19. Draw a neat diagram of a DC motor and label A. ABCD – Rectangular coil of insulated copper wire N & S – Powerful poles of a bar magnet S1 and S2 – Split ring commutator B1 and B2 – Carbon Brushes

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20. Draw a graph of induced current in each of AC and DC dynamo.A.

21. Who discovered the magnetic effect of electric current? A. Orested discovered magnetic effect of electric current22. What is magnetic effect of electric current?A. When electric current is passed through a conductor it develops a magnetic field around it, this effect is called magnetic effect of electric current.23. What is a commutator?A. A commutator periodically reverses the current direction in the external circuit in an electrical motor. It ensures that the current is flowing in the same direction,24. Name the type of current supplied to home.A. AC current is supplied to home.25. On what Principle does the following works?A. a) Dynamo: Principle of Electromagnetic Induction b) Motor: Force acting on a current carrying conductor placed in magnetic field26. Current is measured by the unit of ___________a. Newton b. Ampere c. Ohm d. Volt27. A change in magnetic field produce an electric field this was discovered by __________a. Maxwell b. Faraday c. Fleming d. Ritter28. Which of the following used by faraday to detect the current in coil-magnet experiment_____a. Current detector b. Galvanometer c. Ammeter d. All the above29. The current in a coil due to change in magnetic flux linked with a coil is known as ______a. Supplied current b. Dynamic current c. Induced current d. None of the above30. Dynamo is based on the principle of __________________a. Law of conservation of energy b. Electromagnetic Induction c. Electro-chemical process d. Electromagnetic conduction.31. Armature is known as ___________a. Rings with load b. Rings with Circuit C. Wire along the rings d. Both b and c32. Which rule is used to find the direction of current in AC dynamo_______________a. Faraday’s Law b. Right hand rule c. Fleming’s Right hand rule d. Flemings left hand rule33. Alternating current is produced by __________ a. Dynamo b. AC generator c. DC Dynamo d. Battery34. Dynamo converts _____________a. Mechanical energy to potential energy b. Mechanical energy to electrical energyc. Electrical energy to mechanical energy d. Electrical energy to kinetic energy35. In Fleming’s left hand rule direction of induced current is given by ______________a. Thumb b. Forefinger c. Central finger d. Main finger

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36. An electric current passing through a conductor produces a magnetic field around it is called a. Magnetic effect b. Magnetic field c. emf d. Electromagnetic induction37. The SI unit of potential difference is ___________________a. Ampere b. Volt c. Joules d. ohm38. The motion in which the magnet is at rest and the coil is moved is ____________a. Circular motion b. Rotatory motion c. Relative motion d. Oscillation39. The brushes in the dynamo is made up of _______________a. Sulphur b. Silicon c. Carbon d. Aluminium40. The device that makes the current flow in one direction in the external circuit_____________a. Armature b. Field magnet c. Commutator d. Galvanometer41. The other name for Dynamo is ___________ a. Generator b. Commutator c. Diode d. Motor42. For producing electric current there must be ____________________a. Change in magnetic field b. Change in electric field c. Change in strength of the magnetd. Change in strength of the coil43. Motor force is a maximum when the angle between the direction of current and the magnetic field is ______________ a. 00 b. 450 c. 900 d. 1800

44. Brushes and connecting wires together with the load are called ____________a. Armature b. Couple c. External Circuit d. Internal Circuit 45. Among the following the one in which motor is not used is ________________a. Electric crane b. Mixer c. Electric fan d. Electric Iron Box46. A motor works on the principle of _______________________a. Conductor carrying current in a magnetic field experiences a mechanical forceb. Electromagnetic Induction c. Faraday’s Law d. none of these47. Volt is the unit of which of the following quantities?a. Electric current and potential differenceb. Potential difference ad electromotive forcec. Electromotive force and resistanced. Electrical resistance and current48. North pole of a bar magnet is continuously thrust in and pulled out of the coil of conductor connected to a galvanometer several times, then the pointer of the galvanometera. remains at zero b. deflects on either side of the zero c. moves towards the left side of the zerod. deflects towards the right side of the zero49. In a conductor, a changing magnetic field linking the conductor inducesa. resistance b. motor force c. electromotive force d. magnetic force50. The best and the easy method out of the following to get maximum emf from a dynamo purchased bya) Increasing the number of turns b. Increasing the strength of the magnet c. Increasing the speed of rotation of the coil d. covering the dynamo by an insulator.

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