Question

9. Four capacitors each having capacitance of 2 pF are connected such that the combination
has the least possible capacitance. The capacitance of the combination is
a12 pF
b) 8 HF
c)0,5 mF
d) 1 uF
10. The electnc potential at a point on an equatonal line of an electric dipole is
2kp
kp
b),
d)
11. Two charges 2 uC and 4 uC are separated by 20 cm. The electrostatics force between the
12 A 4 Volt battery is connected to a 3 uF capacitor. The charge on the plate of the capucitoris
13. A gold leaf electroscope is positively charged. A positive charge is now brought close to the
knob of the electroscope the leaves
14. The dimension of Electric field intensity is​

Answer 1

Answer:

Here C1,C2,C3 are in series and the equivalent resistance for these is C123=30/3=10μF

Now C123,C4 are in parallel. So the net capacitance Cnet=C123+C4=10+30=40μF

Now potential across C123 and C4 is same i.e, 60V

So energy stored in C4 is U4=21C4V2=0.5×30×10−6×602=0.054J=54mJ

As C1,C2,C3 are in series so they have same charge is equal to Q123=C123V=10×60=600μC

Stored energy, U1=2C