Advertisements
Advertisements
Question
In the circuit shown below, the voltmeter reads 10 V.
(a) What is the combined resistance?
(b) What current flows?
(c) What is the p.d. across 2 Ω resistor?
(d) What is the p.d. across 3 Ω resistor?
Advertisements
Solution
(a) The resistors of 2 Ω and 3 Ω are connected in series.
Therefore their combined resistance, R = R1 + R2
Here, R1=2 Ω
R2=3 Ω
So, the combined resistance, R = 2 Ω + 3 Ω
R = 5 Ω
(b) The current, I in the circuit can be calculated as:
V = IR
or I = 10 / 5 = 2 At)=R2R1+R2v(t)
(c) The p.d. across the 2 Ω resistor is:
V = IR
or V = `2xx2` = 4 V
(d) The p.d. across the 3 Ω resistor:
V = IR
or V = 2 x 3
or V = 6 V
APPEARS IN
RELATED QUESTIONS
What does an electric circuit mean?
<p> Define the unit of electric current (or Define ampere).
In 10 s, charge of 25 C leaves a battery, and 200 J of energy are delivered to an outside circuit a result.
What is the p.d. across the battery?
An electric circuit consisting of a 0.5 m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key was set up.
(i) Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points 'X' and 'Y' and the electric current flowing through XY.
In the circuit diagram given below five resistances of 10 Ω, 40 Ω, 30 Ω, 20 Ω, and 60 Ω are connected as shown to a 12 V battery.
Calculate:
(a) total resistance in the circuit.
(b) total current flowing in the circuit.
Draw a circuit diagram to show how two 4 V electric lamps can be lit brightly from two 2 V cells.
Match the pairs.
| ‘A’ Group | ‘B’ Group |
| 1. Free electrons | a. V/R |
| 2. Current | b. Increases the resistance in the circuit |
| 3. Resistivity | c. Weakly attached |
| 4. Resistances in series | d. VA/LI |
The diagram shows two ways of connecting three lamps P, Q and R to A.C. supply of 220 V.
Tick(✓) the correct choice in the following:
Which of the following quantities has the same value for all electrical
appliances connected to the ring main circuit in a house?
The following appliances are to be used on 240 V supply. Calculate the current used by each and say which fuse, 2 amp, 5 amp or 13 amp should be incorporated with each, (i) A television rated at 150 W, (ii) An electric iron rated at 750 W, (iii) An immersion heater rated at 3000 W, (iv) A hair dryer rated at 500 W. How much will it cost to run the television set for 100 days for an average of 4 hours a day at 60 paise per unit?
Fig. shows a 3 pin plug with the cover removed. The electric cable
connected to the plug contains 3 wires with colour coded insulation namely brown, blue and green.
- Identify each of the colour coded wires by stating to which of the
terminals A, B or C in the diagram they should be connected. - Identify the terminal through which no current passes in normal
circumstances. - What is the purpose of the earthed wire connected to an electric
appliance like an electric heater? Describe how it works.
A 3 pin mains plug is fitted to the lead for a 1 kW electric kettle to be used on a 250 V A.C. supply. Which of the following statements is NOT correct?
(a) A 13 A fuse is the most appropriate value to use.
(b) The brown wire should be connected to the live side of the mains.
The circuit diagram in fig shows two coils of an insulated copper wire wound on a cardboard tube. G is a center zero galvanometer.
(a) Describe what will happen when th e swi tch K is cl osed for severa l
seconds and then opened again .
(b) What will be the effect of repeating the experiment with an iron placed in the tube?
State whether the current is a scalar or vector?
Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. Calculate :
The total current taken from the supply
A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:
The resistance of the bulb
Fill in the blank :
1 mA = ............................. A.
Answer the following question.
An electric lamp of resistance 20 Ω and a conductor of resistance 4 0 are connected to a 6 V battery as shown in the circuit. Calculate: 
(a) the total resistance of the circuit,
(b) the current through the circuit,
(c) the potential difference across the (i) electric lamp and (ii) conductor, and
(d) power of the lamp.
