Basic Electrical Science (Electrostatics)

1. The unit of absolute permittivity of a

medium is

(a) joule/coulomb

(b) Newton-metre

(c) farad/meter

(d) farad/coulomb

2. If relative permittivity of mica is 5, its absolute permittivity is

(a) 5 ε₀

(b) 5/ε₀

(c) ε₀/5

(d) 8.854 × 10^-12

3. Two similar electric charges of 1 C each are placed 1 m apart in air. Force of repulsion between them would be nearly...... newton

(a) 1

(b) 9 × 10⁹

(c) 4 π

(d) 8.854 × 10^-12

4. Electric flux emanating from an electric charge of + Q coulomb is

(a) Q/ε₀

(b) Q/ε_r

(c) Q/ε₀ε_r

(d) Q

5. The unit of electric intensity is

(a) joule/coulomb

(b) Newton/coulomb

(c) volt/metre

(d) both (b) and (c)

6. If D is the electric flux density, then value of electric intensity in air is

(a) D/ε₀

(b) D/ε₀ε_r

(c) dV/dt

(d) Q/εA

7. For any medium, electric flux density D is related to electric intensity E by the equation

(a) D = ε₀ E

(b) D = ε₀ε_r E

(c) D = E/ε₀ε_r

(d) D = ε₀E/ε_r

8. Inside a conducting sphere,...remains constant

(a) electric flux

(b) electric intensity

(c) charge

(d) potential

9. The SI unit of electric intensity is

(a) N/m

(b) V/m

(c) N/C

(d) either (b) or (c)

10. According to Gauss’s theorem, the surface integral of the normal component of electric flux density D over a closed surface containing charge Q is

(a) Q

(b) Q/ε₀

(c) ε₀Q

(d) Q²/ε₀

11. Which of the following is zero inside a charged conducting sphere ?

(a) potential

(b) electric intensity

(c) both (a) and (b)

(d) both (b) and (c)

12. In practice, earth is chosen as a place of zero electric potential because it

(a) is non-conducting

(b) is easily available

(c) keeps losing and gaining electric charge every day

(d) has almost constant potential.

Answers

1. c      2. a      3. b      4. d      5. d      6. a      7. b      8. d      9. d      10. a    11. c    12. d