Electric Circuits Answers

Find the value of the unknown resistance in each case:

a. A 20 Ω, 18 Ω, and an unknown resistor connected in series to give a total resistance of 64 Ω.

b. Two identical unknown bulbs connected in series with 50 Ω and a 64 Ω heater to produce a total resistance of 150 Ω.

Find the total resistance in each of the cases:

a) Three 30 Ohm light bulbs and two 20 Ohm heating elements connected in a series.

b) Two strings of Christmas tree lights if the first string has eight 4 Ohm bulbs in series and the second has twelve 3 Ohm bulbs in series.

A  100 W lamp has steady current of 0.83 A in its filaments. How long is required for 1 mol electrons to pass through the lamp?

You are required to Design 1- series circuit according to your own choice using electronic simulator.

For this, you can use any freely available simulator like Circuit Maker, Dip Trace, or Proteus.

Calculate the charge stored on a 3-pF capacitor with 20 V across it.(b)

Find the energy stored in the capacitor.

An electric circuit is formed of :

_a generator delivering a constant voltage Ugenerator=24 volt

_Resistor D of resistance R=48 ohm

_Rheostat (D') of adjustable resistance R_h

1_Show applying law of addition of voltages that the current is given by the expression:

I=U_generator/R+R_h

2_We vary the value of R_h between two limiting values 0 ohm and 120 ohm.Calculate the value I₁ of I for R_h=0 ohm.Then calculate the value I₂ of I for R_h=120 ohm.

3_Deduce the role of a rheostat in a series connection.

4_Let P be the power dissipated by R.Give the expression of P in terms of R and I.Calculate the value P₁ of P for I=I₁ and the value of P₂ of P for I=I₂

5_The maximum power that the resistor D can stand is 5 watt. Show that resistor D can be damaged only in one of the two limiting values of R_h.

A cell supplies 5600 J of energy when 4200 C of charge moves completely around the circuit. The load resistor is 7.5 ȍ and the potential difference across the load is 1.1 V. Find the emf, the current through the circuit, and the size of the internal resistance of the cell.  

A battery is connected in series with a variable resistor. When the resistor is 8.50 ȍ, the current is 1.00 A and when the resistor is 6.50 ȍ, the current is 1.25 A. What is the value of the internal resistance?

A cell of emf 8.0 V has an internal resistance of 1.7 ȍ and is connected to a 4.9 ȍ resistor. Find the current in the resistor, the power dissipated in the resistor, and the terminal potential difference across the cell.

0.800 watts of power are dissipated in a cell of emf 10.0 volts. If the internal resistance is 2.40 ȍ, find the resistance of the load and the current in the load.