TEST IIENGINEERING SCIENCES II (SSD 12103)

By john jabaraj

Name: ……………………… Class : ………………………1.a} Sketch the electric field lines for these systems of charges.

i) ii) {2m}

b} A butterfly contains 2.2 x 1014 electrons and 3.5 x 1014 protons. It is attracted to a beautiful but

smelly ‘Tahi Ayam’ flower which has a charge of -15C. Calculate the:

P

30m 44m

i) charge of the butterfly.ii) magnitude & direction of the butterflys’ electric field at point P.iii) magnitude & direction of the flowers’ electric field at point P.iv) total electric field at point P. {8m}

2. a} Find the charge value contained in each object below. 2m

i) λ= 9.2C/m ii) ρ= 5.5C/m3

{2m}

11m

b} The test paper that you are holding now is rectangular-shaped. Assume that it contains a value of +0.07 x 10-6C of charge. i) Use a ruler to find the papers’ area, A = length(m) x width(m). {5m}

ii) Calculate the charge distribution in the paper.

iii) Determine the papers’ electric field strength at P. P 1111m

c} Cik Piring is a big-headed girl. The c/s area of her head is 0.55m2. She is placed in various

situations as below. For each situation;i) E= 11N/C ii) E= 14N/C iii) E = {3m}

57

Ø = Ø = 4.4Nm2/C Ø = 7.7Nm2/C

Find the electric flux, Ø. Find the angle, . Find the electric field, E. 3. a} According to this electric circuit, calculate the; 5F 3F

i) total capacitance. ii) voltage and charge at each capacitor.

{4m}

12V

b} Calculate the total capacitance for each circuit. Each capacitor is 5F. {6m}

i) ii) iii)

-:EQUATIONS:-

+ _ _

5m 3m

TEST IIENGINEERING SCIENCES II (SSD 12103)

By john jabaraj

Name: ……………………… Class : ………………………

Electric Charge

Σ Q = ne Qe + np Qp

F = k qa qb

r2

E = k Q r2

E = F / q

Gauss Law & Electric Potential Energy Ø = E A cos

∫ E . dA = Q / εo

λ = Q / L σ = Q / A ρ = Q / V

E = kQ / r2 E = λ / 2π εo r E = σ / 2 εo

W = q E d = q V

V = E d

Capacitance & Dielectric

C = Q / V

C = εo A / d

Cdie = K C

Energy = ½ C V2

C TOTAL = C1 + C2 + C3 … { parallel }

1 = 1 + 1 + 1 … { series }C TOTAL C1 C2 C3

Qe = -1.602 x 10-19 C, Qp = +1.602 x 10-19 C, k = 9 x 109 Nm2 / C2, εo = 8.85 x 10–12 C2 / N m2