Electric Circuits Answers

4. A current of 4 A flows through a resistor, and the voltage across the resistor is 32 V.
a) What is the power dissipated by the resistor?
b) How much energy is dissipated by the resistor in 20 s?
c) What is the resistance of the resistor?

3. A car headlight may put out 100 W at 25 V.
a) Calculate the current drawn by the headlight.
b) How many electrons pass through the bulb filament each second?

2. The resistance of a certain wire is 10 Ω. a) What would the resistance of the same wire be if it were twice as long? b) If it had twice the diameter?

A galvanometer of resistance 50 ohm which gives a full scale deflection for 1mA is to be adapted to measure currents of up to 5A if this resistor is made of a material of cross sectional area 4×10^-4 and resistivity 2×10^-6. Calculate it's length

State with reasons whether the following statements are True or False.i) Bandwidth of frequency modulated (FM) signal is narrower than that of amplitude modulated (AM) signal.
ii) Amplitude shift keying is modulation of digital carrier by analog signal.
iii) GSM is a spread spectrum technology.
iv) TRF receivers are preferred over super-heterodyne receivers in audio communication.
v) Schottky diode can handle higher frequency signals than p-n junction diode.

Do charged particles need to be confined to a wire? Why or why not? Give an example that supports your answer.

The armature of a small generator consists of a flat, square coil with 120 turns and sides
with a length of 1.6 cm. The coil rotates in a magnetic field of 0.075T. What is the
angular speed of the coil if the maximum emf produced is 24.0mV?

If 50 cm of wire were used in heating the element of a 6 V, 30 W heater, what length of wire of the same material having double the cross - sectional area would be required for a 12 V, 30 W heating element , assuming that the final temperature is the same?

A straight, cylindrical wire lying along the x axis has a length of 0.500 m and a diameter of 0.200 mm. it is made of a meterial described by Ohm's law with a with a resistivity of p=4.00 *10^-8 Ohm . m. Assume a potential of 4.00 V is maintained at the left end of the wire at x=0. Also assume V=0 at x=0.500 m. Find a) the magnitude and direction of the electric field in the wire , b) the resistance of the wire, c) the magnitude direction of the electric current in the wire, and d) the current density in the wire. e) Show that E=pJ

A 500-W heating coil designed to operate from 110 V is made of Nichrone wire 0.0500 mm in diameter a) assuming the resistivity of the Nichrone remains constant at its 20.0 degrees celcius , find the length of wire used. b) What if? Now consider the variation of resistivity with temperature . what power is delivered to the coil of part a) when is is warmed to 1200 degrees celcius?