Electromagnetic Induction – Exercise – 1

6. In pure inductance, the average power dissipated is :

(a) 1
(b) greater than 1
(c) less than 1
(d) zero

7. When an iron core is inserted into a coil, its coefficient of self induction :

(a) increases
(b) decreases
(c) remains the same
(d) becomes zero

8. The dimensions of ‘self inductance’ and ‘magnetic flux’ are :

(a) M L T –2 and M L 2 T –1 A –1 respectively
(b) M L 2 T –2 A –2 and M L 2 T –2 A –1 respectively
(c) M 2 L -1 T –1 and M 2 L 2 T –2 respectively
(d) MTndash;2Andash;1and M2LT respectively

9. If L1 and L2 are the self inductance of two coils then the mutual inductance between them is :

(a) M = K (L1L2)
(b) M = K √(L1/L2)
(c) M = K√(L1L 2)
(d) M = K(L1L2)2

10. Eddy current may be appreciable in many cases. It heats metals and so a wastage of electrical energy noticed. This is undesirable in transformers, induction coil and choke coil. This can be minimised by using :

(a) laminated cores in transformers
(b) using bundles of soft iron rods in induction coils
(c) using glass surfaces
(d) all are false

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