Each of the uncharged capacitor in the fig.Has a capacitance of 25\(\mu \)F. what charge shall flow through the meter M when the switch S is Closed?

1

(a)

C = C+C+C = 3C = 75\(\mu \)F
Therefore m charge  = 75\(\mu \)F x 4200V = 315 mC.

Charge of 2C is placed at the centre of a cube volume 8 cm³. What is the electric flux passiing through one face?

1

(a)

Toral \(\phi \) = q0/\({ \varepsilon }_{ 0 }=2/{ \varepsilon }_{ 0 }\), \(\rightarrow\) flux through one face  = \(\phi \)/6 = 1/3 \({ \varepsilon }_{ 0 }\)

Find the equivalent capacitance between A & B , if Capacitance of each Capacitor is C

1

(a)

Eq. network is the Eq.capacitance
= (2C series C) || (2C series C)
= 4C/3

Eight identically charged drops are joined to form bigger drop. By what factor the charge and potential change?

1

(a)

4/3 \(\pi\)R³ = 8 x 4/3\(\pi\)r³

Three charges Q, +9 and +9 are placed at the vertices of a right angle isosceles triangle as shown, Find the magnitude of Q for which net electrostatic  energy of the configuration is zero. 

1

(a)

U = K (q²/a + qQ/a +qQ/2a)
But U = 0
Therefore ,Q -2q/(2 + \(\sqrt { 2 } \))