Electric Circuits Answers

A nichrome wire is 1.0m long and
1.0mm2 in cross-sectional area. It carries a current of 4.0 A when a potential difference of 2 V is applied between its ends. Calculate the conductivity of the wire.
a. (2MΩm)−1
b. (4kΩm)−1
c. (2mΩm)−1
d. (4Ωm)−1

A polythene rod resting on two watch glasses which are as a low friction pivot. A negatively charged rod is brought near the polythene rod. If the polythene rod is attracted what are two conclusions

Two large horizontal metal plates are separated by 4 mm. The lower plate is at a potential of
−6V. What potential should be applied to the upper plate to create electric field strength of 4000 V/m upwards in the space between the plates?

a. +22V
b. +10V
c. −10V
d. −22V

An air-cored transformer is assumed to be 100% efficient. The ratio of the secondary turns to the primary turns is 1:20. A 240V ac supply is connected to the primary coil and a 6Ω load is connected to the secondary coil. what is the current in the primary coil?

a. 0.10A
b. 0.14A
c. 2.0A
d. 40.0A

A voltmeter connected across a 60Hz ac source reads 240V. Write down the expression of the instanteneous voltage as a function of time.

a. 240sin339.4t
b. 339.4sin377t
c. 377cos339.4t
d. 240cos339.4t

An ac circuit consists of a voltage source
v=200sin120πt and a 6μF capacitor in series. Calculate the current established in the circuit
a. 0.32A
b. 1.24A
c. 0.64A
d. 2.13A

A galvanometer of resistance
120Ω
a full scale deflection with a current of 0.0005A. How would you convert it to an ammeter that reads a maximum current of 5A?

A galvanometer of resistance 120Ω a full scale deflection with a current of 0.0005A. How would you convert it to an ammeter that reads a maximum current of 5A?
a. connect
2000Ω
in parallel to it
b. connect
200.12Ω
in series to it
c. connect
20.10Ω
in series to it
d. connect
0.012Ω
in parallel to it

A galvanometer with coil resistance 12.0Ω shows full scale deflection for a current of 2.5mA. How would you convert it into a voltmeter of range 0 to 10.0V?
a. 3988Ω
in series
b. 0.43Ω
in parallel
c. 2000Ω
in parallel
d. 1.62Ω
in series

A solid metal contain 16*1000000000000000000000 atom . If 5% of electron comes out of total atom, then what will be the charge of solid.