Electromagnetic Induction MCQs
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Hysteresis losses can be reduced by
- A. using grain-oriented silicon steel
- B. increasing the frequency of the field
- C. laminating the core
- D. none of these
- Correct Answer: Option A
A degaussing is the process of
- A. removing gases from materials
- B. removal of magnetic impurities
- C. demagnetizing metallic part
- D. magnetizing nonmettalic part
- Correct Answer: Option C
According to Hysteresis law, hysteresis loss in a material is proportional to
- A. B^1.2
- B. B^1.6
- C. B^0.6
- D. B^3.6
- Correct Answer: Option B
The area of hysteresis loop represents hysteresis loss in
- A. J/ m^3/s
- B. J/cycle
- C. J/s
- D. J/m^3
- Correct Answer: Option A
In electrical machines, laminated cores are used with a view of reducing
- A. eddy current loss
- B. copper loss
- C. hysteresis loss
- D. windage loss
- Correct Answer: Option A
It is difficult to magnetize steel because its
- A. low permeability
- B. high retentivity
- C. high permeability
- D. high density
- Correct Answer: Option A
The coupling coefficient denotes
- A. the degree of magnetic linkage
- B. whether the reluctance remains constant
- C. the variation of inductance between the two coils
- D. whether the flux linkage is constant
- Correct Answer: Option A
Coupling coefficient k, a term much used in radio work can be obtained from
- A. K = M√(L1L2)
- B. K = M√(L1/L2)
- C. K = M/√(L1L2)
- D. K = ML1L2
- Correct Answer: Option B
The value of mutual inductance in terms of self inductance of the two coils L1 and L2 is proportional to
- A. L1L2
- B. L1/L2
- C. √(L1/L2)
- D. √(L1L2)
- Correct Answer: Option D
The mutual inductance of two coils is maximum when the coils are
- A. inclined at an angle 45 degrees
- B. at right angle to each other
- C. facing each other
- D. touching each other
- Correct Answer: Option D