Electric Circuits Answers

Two identical metal plates are given +ve charge Q1 and Q2 (<Q1). If they are brought closer to form a parallel plate capacitor of capacitance C ,then pot diff across C is?
a)Q1+Q2/2C
b)Q1+Q2/C
c)Q1-Q2/2C
d)Q1-Q2/C

twelve capacitors of capacitance 7microfarad each are joined in 12 sides of a cube. What is equivalent capacitance b/w any two adjacent corners of cube??
a)12 microfarad
b)49/12mf
c)35/6mf
d)8mf
mf is microfarad

A step down transformer is connected to main supply 200V to operate a 6V-30W bulb.The current in primary-
A)3 Amp. B)0.3 Amp. C)1.5 Amp. D)0.15 Amp.

In the normal operation of a bipolar transister. what is the biasing of emitter base and collector base function.

The difference of potencial between the terminal of a cell in an open circuit is called

How much energy is given to each coulomb of charge passing through a6v battery?

An air-filled parallel-plate capacitor has a capacitance of 1 pF. The plate separation
is then doubled and a wax dielectric is inserted, completely filling the space between the
plates. As a result, the capacitance becomes 2 pF. The dielectric constant of the wax is:
A. 0.25
B. 0.5
C. 2.0
D. 4.0
E. 8.0

The potential difference V and the current i flowing through an instrument in an ac circuit of frequency f are given by V = 5 cos t volts and I = 2 sin t amperes (where = 2f). The power dissipated in the instrument is -
(1)Zero
(2)10 W
(3)5 W
(4)2.5 W

dc supply is 10 volts. describe how the current through the circuit and the voltage across the capacitor will develop when the switch is closed, and how this is affected by the resistor value