Page 96 - Basic Electrical Engineering

[Ans M = 0.5 H, 0.75]

46. Calculate the inductance of a coil having 100 turns wound on a magnetic core of permeability
2
equal to 1000, mean length of 0.25 m, and cross-sectional area of 10 cm .

[Ans L = 50.24 mH]

2
47. A conductor of length 25 cm is placed in a uniform magnetic field of strength 0.5 Wb/m .
Calculate the EMF induced in the conductor when it is moved at the rate of 10 m/sec (a)
parallel to the magnetic field, (b) perpendicular to the magnetic field.

[Ans (a) 0 V; (b) 1.25 V]

Multiple Choice Questions

1. The number of electrons per Coulomb is equal to

a. 1.602 × 10 −19
18
b. 6.28 × 10
18
c. 1.602 × 10
d. 6.28 × 10 −19 .

2. In insulators the outermost orbit of their atoms is filled with

a. 4 electrons
b. 8 electrons
c. 1 electron
d. 18 electrons.

3. In the atoms of semiconducting materials like silicon and germanium the outermost orbit has

a. 1 electron
b. 2 electrons
c. 8 electrons
d. 4 electrons.

4. Which of the following expressions is incorrect?

a.

b. Charge = current × time