Electric Circuits Answers

Two identical light bulb, each with resistance R = 2􀀺 are connected to a source with E = 8

V and negligible internal resistance. Find the current through each bulb. The potential

difference across each bulb and the power delivered to each bulb and to the entire network

if the bulbs are connected parallel

A battery of EMF E and internal resistance r is connected across a variable resistor. When the resistor is set at 2lΩ the current through it is 0.48A; when it is set at 36Ω. the current is 0.30A. Find E and r.

An electric lamp rated 200w,240v operates for a time interval of 5 minutes calculate

(a)resistance of the lamp

(b)current flowing through the lamp

(c)electrical energy of the lamp

The resistance of a copper wire increases by a factor of 1.62 when current flows through the wire compared to its resistance when no current flows and its temperature is 20o C. What is its temperature when the current flows?

A platinum resistance thermometer consists of a coil of 0.10-mm-diameter platinum wire wrapped in a coil. (a) What is the length of the wire needed so that the coil’s resistance at 20^o C is 25 Ω. The resistivity of platinum at this temperature is 1.0 x 10^-7 Ω.m. (b) What is the temperature of this platinum wire when its resistance increases 35% of its initial temperature? The temperature coefficient of resistivity for platinum is 3.92 x 10^-3 /^o C.

Three charges lie along the x - axis. A positive charge q1 = 10 𝝁C is at x = 1.00 m, and a negative charge q2 = – 2.0 𝝁C is at the origin. Where must a positive charge q3 be placed on the x - axis so that the resultant force on it is zero?

A 100-m-long copper wire of radius 0.12 mm is connected across a 1.5-V battery has 9.4 x 10¹⁹ electrons passing a cross section of the wire every 3.0 s. Calculate the resistance of this wire.

A 240-turn solenoid is 80.0cm long and carries a current of 0.30A. Calculate the magnitude of the magnetic field at the center of solenoid.

A battery powered torch uses a 9 V battery and dissipates 0.25 W of electrical power in the bulb.

If the torch is used for 1.0 hours then how much charge has passed through the bulb?

A portable television using a 12V, 3Ah rechargeable battery can operate for a period of about 6 h. What is the average current drawn during this period?