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T-4 (Chapter 15)

1) The document is a physics exam paper containing multiple choice and short answer questions testing knowledge of electromagnetic induction and transformers. 2) The multiple choice section contains 8 questions worth 1 mark each testing concepts like induced emf, current, units of mutual inductance, energy storage in inductors. 3) The short answer section contains 7 questions worth 2 marks each about topics such as dependence of induced emf and current on resistance, conditions for no induced emf, direction of induced current according to Lenz's law, units of mutual inductance, converting a DC motor to generator, power losses in transformers and reducing them, and definition and factors affecting mutual inductance. 4)

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Muhammad Awais
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97 views1 page

T-4 (Chapter 15)

1) The document is a physics exam paper containing multiple choice and short answer questions testing knowledge of electromagnetic induction and transformers. 2) The multiple choice section contains 8 questions worth 1 mark each testing concepts like induced emf, current, units of mutual inductance, energy storage in inductors. 3) The short answer section contains 7 questions worth 2 marks each about topics such as dependence of induced emf and current on resistance, conditions for no induced emf, direction of induced current according to Lenz's law, units of mutual inductance, converting a DC motor to generator, power losses in transformers and reducing them, and definition and factors affecting mutual inductance. 4)

Uploaded by

Muhammad Awais
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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Class Part-II Subject Physics Time Allowed 60 Minutes

Q.Paper-I Objective Type Paper Maximum Marks 30


Roll No. Student Name Date
Syllabus Ch # 15

Q. No 1: Attempt the following mcq’s and choose the correct option. (8 × 1 = 8)

1. If 1V of induced emf is produced in a wire of resistance 2 ohm, then induced current will be:
(a) 0.2 (b) 0.3 (c) 0.4 (d) None
2. A.C current reverses its direction:
(a) T times per sec (b) f times per sec (c) One per sec (d) None
3. The Unit of mutual inductance is ____:
(a) Henry (b) VsA-1 (c) Wb/A (d) All
4. The quantity that remains unchanged in a transformer is:
(a) V (b) I (c) f (d) None
5. It converts electrical energy into mechanical energy
(a) A.C. generator (a) D.C. generator (b) Cell (c) D.C motor
6. If 10 A current pass through 100 mH inductor, then energy stored is:
(a) 100 J (b) 5 J (c) 20 J (d) Zero
7. The Lenz’s law refers to:
(a) induced current (b) induced emf (c) motional emf (d) charge
8. An inductor may store energy in the form of:
(a) Electric field (b) magnetic field (c) electric charge (d) All

Q. No 2: Attempt the following SHORT QUESTIONS (7 × 2 = 14)


1. Does the induced emf in a circuit depend on the resistance? Does the induced current depend upon the
resistance of the circuit?
2. Is it possible to change both the area of the loop and magnetic field passing through the loop and still
not have induced emf?
3. Does the induces emf always act to decrease the magnetic flux through the coil?

4. Show that and have the same units.


5. Can a DC motor, be turned into a DC generator? What changes are required to be done?
6. What are power losses in transformer? How can we reduce it?
7. Define mutual inductance? On which factors it depends?

Q. No 3: Attempt the following LONG QUESTION. (5 + 3 = 8)

1. (a) State and explain the faraday’s law of electromagnetic induction.


(b) A square loop of side 16 cm has 200 turns and rotates in a uniform magnetic field of magnitude
of 0.05 T. If the peak value is 12 V, what is the angular velocity of the coil?

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