VIKASANA 2014 CET Training Classes ELECTROMAGNETIC INDUCTION
1. In Faraday s coil and magnet experiment, the galvanometer shows deflection: a. when the coil & the magnet are stationary b. only when the magnet moves c. only when the coil moves d. when there isarelative motion between the coil and the magnet
2. Faraday s law of electromagnetic induction states that the emf induced in a circuit is: a. directly proportional to the density of field lines b. inversely proportional to the rate of change of density of field lines c. directly proportional p to the magnetic field d. directly proportional to the rate of change of density of field lines
3. The directioni of the induced d current in electromagnetic induction i isgiveni by: a. Kirchhoff s law b. Faraday s law c. Lenz s law d. Biot Savart s law
4. Lenz s law is a consequence of the law of conservation of: a. momentum b. charge c. mass d. energy
5. The magnetic flux through a surface placed in a magnetic field can be changed by: a. changing the magnetic field b. changing the area of the surface c. rotating the surface d.all of the above
6. The SI unit of magnetic flux is: a. T b. Tm 2 c. Tm 2 d. Wb m 2
7. A motional emf is induced d in arod moving in amagnetic field. The material of the rod can be: a. glass b. rubber c. wood d. iron
8. If rods of negligible thickness and equal lengths made with iron, copper and gold are moved in a magnetic field, then for which rod the motional emf is maximum? a. Iron b. Copper c. Gold d. Same for all of them
9. The value of the motional emf induced d in a metal rod of length l moving with ihavelocity v parallel l to a magnetic field B is: a. zero b. Blv c. Blv/2 d. 2 Blv
10. Eddy currents are: a. induced currents due to changing magnetic flux b. induced currents due to high magnetic flux c. induced currents in an insulator d. all of the above
11. Eddy currents produce: a. heating effect b. damping effect c. cooling effect d. both a and b
12. The principle of an induction furnace is: a. self induction b. mutual induction c. eddy currents d. motional emf
13. The phenomena of induction i of an emf in acoil due to a change in currentthrough h it is called: a. self induction b. mutual induction c. eddy currents d. hysteresis
14. The self inductance of a coil depends on: a. the number of turns b. the nature of material inside the coil c. the physical dimensions of the coil d. all of the above
15. The principle of choke coil is: a. self induction b. mutual induction c. eddy currents d. motional emf
16. The phenomena of induction i of an emf in a secondary coil due to a change current through h the primary coil iscalled: a. self induction b. mutual induction c. eddy currents d. hysteresis
17. When an iron rod is introduced into a solenoid coil, its self inductance: a. increases b. decreases c. remains the same d. may increase or decrease
18. Self inductance is a measure of: a. electrical inertia b. induced emf c. induced current d. mass of the coil
19. An inductance coil: a. allows ac easily b. allows dc easily c. allows both ac and dc easily d. does not allow current through it
20. Which one of the following device works on the principle of mutual induction? a. Voltmeter b. Ammeter c. Transformer d. van de Graff Generator
21. A self inductor stores energy in the form of: a. electric field b. magnetic field c. both electric and magnetic fields d. kinetic energy
22. In an induction coil, the secondary emf is: a. zero during the make of the circuit b. very high during the break of the circuit c. zero during the break of the circuit d. very high during the make of the circuit
23. An AC generator converts: a. heat energy into mechanical energy b. electrical energy into mechanical energy c. mechanical energy into electrical energy d. electrical energy into heat energy
24. AC in India is rated with: a. 220 V, 50 Hz b. 110 V, 60 Hz c. 220 V, 60 Hz d. 110 V, 50 Hz
25. As the angular speed of the rotating coil of the generator is increased, the peak emf: a. increases b. decreases c. suffers no change d. may increase or decrease
1 2
6 7
i 6 f 7
1 2
1 0 5 5 5 5
2 4 1 0
1 1 1 1
B = 4 T
2 3
Given l l
1 2
1 2
1 2 SERIES
1 2 PARALLEL
1 1 2 2
2 0 0 0 0
2 0
4
7 1 8 1 16 1
Given: Magnetic field, B = 1 T Magnetic energy density = Electric energy density Electric field =?
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